A pressure-sensitive adhesive (PSA) is a permanently tacky adhesive that bonds at room temperature under light pressure, with no cure, no solvent loss at the user and no phase change. Among industrial adhesive chemicals, the PSA is the one that arrives at the user already finished: its bond strength depends on flow at the moment of contact and on cohesion afterwards, both fixed by the formula on the coating line.
Pressure-sensitive adhesives come in acrylic, rubber-based and silicone chemistries, each made as a permanent, removable or repositionable grade. Rubber grades build on natural rubber, styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS) block copolymers or polyisobutylene (PIB); silicone grades combine a polydimethylsiloxane (PDMS) gum with an MQ silicate resin.
This page gives three published starting formulas with lab results, tackifier levels with their basis by end use, the bonding threshold of 3 × 10⁵ Pa at 25 °C and 1 Hz, the current ASTM and EN ISO test editions, the limits of 21 CFR 175.125 for food labels, the coating-line emission rules and the Annex VI lines of acrylic monomers and dibenzoyl peroxide.
Sources and checks: identities and hazard classifications are read at ECHA and the issuing regulator, standards at the body that publishes them, and grade values at the data sheet named next to them; methodology and fact-checking explains each step.
What Is a Pressure-Sensitive Adhesive?#
A pressure-sensitive adhesive is a permanently tacky material that adheres at room temperature with light (finger) pressure and no phase change, which is how the Pressure Sensitive Tape Council (PSTC) defines the adhesive layer of a PSA tape. The definition excludes every adhesive that must dry, cool or react after the parts meet. A PSA stays a soft, viscoelastic solid for its whole service life, so the same layer that grabs on contact must also carry the load later.
The adhesive reaches the user on a carrier. PSTC names paper, film, foil, nonwoven and cloth as tape backings; labels carry the adhesive over a release liner, and transfer films carry it with no backing. "PSA glue" or "pressure-sensitive glue" in industrial buying means the same chemistry sold unsupported, as a solution, dispersion or hot melt that the converter coats onto its own backing.
How Do Pressure-Sensitive Adhesives Work?#
Pressure-sensitive adhesives work by wetting: under light pressure during a short contact, the soft polymer flows into the roughness of the surface and creates true molecular contact. Flow here is viscous flow of a solid adhesive layer, not the spreading of a liquid, so the rate of bonding depends on pressure, contact time and the softness of the adhesive at room temperature.
How long does a PSA take to dry? A PSA needs no drying, cooling or cure at the user, because the adhesive was dried or cured on the coating line before it was wound up. The bond builds with dwell instead: contact area keeps growing after application, so a peel value is meaningful only with its dwell time.
Bonding and Debonding: Why a PSA Must Both Flow and Resist Flow#
A PSA must flow during bonding and resist flow during debonding, because both events load the same layer at different rates. Bonding needs a storage modulus G' below 3 × 10⁵ Pa (0.3 MPa) at 25 °C and 1 Hz, the Dahlquist criterion (Dahlquist, 1969); a stiffer layer cannot wet the surface on light contact.
Debonding needs cohesion and energy dissipation, read from the storage modulus G' and the loss modulus G'' over frequency, a viscoelastic window concept described by Chang (Journal of Adhesion, 1991). Tack and the Dahlquist criterion together explain why a PSA formula has to be soft at slow bonding rates yet strong at fast peel rates; the measurement side is covered under tack and the Dahlquist criterion.
What Are Pressure-Sensitive Adhesives Made Of?#
A pressure-sensitive adhesive is made of a base polymer (acrylic, rubber or silicone), a tackifier, in rubber grades a plasticizer or oil, a crosslinker and an antioxidant: the polymer gives cohesion, the tackifier tack and peel, the crosslinker shear. The table lists each raw material with its share in published PSA formulas and the basis of that share.
| Function | Family hub | Substances | Share in published PSAs (basis, source) |
|---|---|---|---|
| Base polymer | base polymers for adhesives | acrylic polymers, SIS, SBS, natural rubber, polyisobutylene, butyl rubber, silicone polymers and MQ resins | SIS 31 wt % of formulation (Dalley label hot melt, ASI 2015); acrylic copolymer 100 parts (US patent 6,280,557 B1 examples); PDMS gum as the balance to MQ resin |
| Acrylic monomers | monomers for acrylic PSAs | 2-ethylhexyl acrylate, n-butyl acrylate, methyl methacrylate, acrylic acid | 2-ethylhexyl acrylate 60 / n-butyl acrylate 35 / acrylic acid 5 wt % of monomers (Czech et al. 2022); emulsion grades soft monomer 70 to 90, hard monomer 10 to 30 wt % (Di Lorenzo et al. 2024) |
| Tackifier | tackifier resins | C5 hydrocarbon resin, rosin esters | C5 resin 41.6 + liquid C5 resin 27 wt % of formulation (Dalley); dispersions 10 to 50 % dry resin on dry polymer across four end uses (ASI 2006); MQ resin about 40 to 70 parts per 100 parts resin plus gum (EP0524776A1) |
| Plasticizer, oil | plasticizers for adhesives | process oils, polybutene | naphthenic oil 10 to 50 wt % across SIS research systems (Europe PMC PMC9606934); plasticizer 5 and 7.5 parts per 100 polymer in two examples of US patent 6,280,557 B1 |
| Crosslinker | functional additives for adhesives | crosslinkers, benzoyl peroxide | aziridine 0.1 to 0.9 wt % or aluminum acetylacetonate up to 0.55 wt % on polymer (Czech et al. 2022); dibenzoyl peroxide 1.5 pph on silicone (Antosik et al. 2023, lab) |
| Antioxidant | antioxidants for adhesives | antioxidant 1010 | 0.4 wt % (Dalley); 0.3 to 0.5 wt % of formulation in styrenic block copolymer (SBC) hot melts (Kraton, ASI 2007); antioxidant 1010 at most 1.0 % of a 21 CFR 175.125 PSA (21 CFR 178.2010) |
| Solvent | solvents in adhesives | ethyl acetate, toluene | ethyl acetate at 50 % polymer (Czech et al. 2022); toluene to 50 wt % polymer (Antosik et al. 2024) |
The monomers and solvents in the table belong to acrylic and silicone grades only; a rubber hot melt PSA contains neither.
Base Polymers of a Pressure-Sensitive Adhesive#
Acrylic copolymers are the base polymer of acrylic PSAs, built from 70 to 90 wt % soft monomer and 10 to 30 wt % hard monomer in emulsion grades. The soft monomer, n-butyl acrylate (BA) or 2-ethylhexyl acrylate (2-EHA), keeps the glass transition low; the hard monomer, methyl methacrylate (MMA), adds cohesion. Acrylic acid carboxyl groups raise cohesion by hydrogen bonding, improve adhesion to polar surfaces and provide sites for external crosslinkers; in the solvent formula of Czech and co-workers (2022), acrylic acid is 5 wt % of the monomers.
Rubber PSAs use tackified natural rubber, styrenic block copolymers (SBC) such as SIS and SBS, styrene-butadiene rubber (SBR), polyisobutylene or butyl rubber, applied from solvent, as a hot melt or as a latex. Natural rubber grades may be crosslinked for heat resistance. Silicone PSAs work differently: a high-molecular-weight PDMS gum forms the elastic network, and the low-molecular-weight MQ resin acts as the tackifier.
Tackifiers and Plasticizers in Pressure-Sensitive Adhesives#
A tackifier lowers the modulus of a PSA at bonding rates while raising its glass transition temperature (Tg), tack and peel. Rubber PSAs take C5 hydrocarbon resins, water-based acrylics take rosin ester or hydrocarbon resin dispersions, and silicone PSAs take MQ resin, which in a silicone formula raises peel and shear but lowers tack as its share grows.
Plasticizers and oils soften a rubber PSA and lower its viscosity. Naphthenic oil spans 10 to 50 wt % of formulation across SIS research systems, so the oil share is a design variable rather than a fixed recipe value. More oil gives a softer layer with lower melt viscosity, but it also dilutes the elastomer network that carries static load.
How Crosslinking and Stabilizers Finish a PSA Formula#
Crosslinkers finish an acrylic PSA by reacting with its carboxyl groups, and a silicone PSA by reacting with its methyl groups. Metal chelates form coordination bridges, aziridines ring-open and isocyanates form amide links with the acid groups; peroxides abstract hydrogen from Si-CH3 groups to crosslink silicone. Higher crosslink density raises shear, shear adhesion failure temperature (SAFT) and shrinkage resistance and lowers tack and peel. In the Czech formula, crosslinker is dosed on polymer: aziridine 0.1 to 0.9 wt % or aluminum acetylacetonate (AlACA) up to 0.55 wt %.
Antioxidants protect unsaturated rubbers against oxidation during hot melt coating and in service. The Dalley label formula carries 0.4 wt % antioxidant, and 0.3 to 0.5 wt % of formulation is the level stated for SBC hot melts (Kraton, Adhesives and Sealants Industry, 2007).
Pressure-Sensitive Adhesive Formulation#
Pressure-sensitive adhesive formulation trades tack against shear: in the published examples below, tackifier resins make up 68.6 wt % of a rubber hot melt, while a solvent acrylic relies on its monomer ratio and under 1 wt % crosslinker. These are published examples with lab results, not recommendations. Each one fixes a different lever: resin share in rubber, crosslinker type and dose in acrylic, peroxide dose in silicone.
Three Published Starting Formulas: Rubber Hot Melt, Solvent Acrylic and Silicone#
Three published starting formulas cover the main PSA chemistries; the table gives each component with its basis and the lab results the sources report.
| Component | Rubber hot melt label PSA (Dalley, ASI 2015) | Solvent acrylic PSA (Czech et al. 2022) | Silicone PSA (Antosik et al. 2024) |
|---|---|---|---|
| Base polymer | SIS 31 wt % | 2-ethylhexyl acrylate 60 / n-butyl acrylate 35 / acrylic acid 5 wt % of monomers; Mw 825,000 Da, Mn 280,000 Da | DOWSIL 7358 silicone PSA |
| Tackifier | C5 resin (softening point 95 °C) 41.6 wt %; liquid C5 resin (10 °C) 27 wt % | none stated | none added |
| Antioxidant | 0.4 wt % (sum 100 wt %) | none stated | none stated |
| Solvent and initiator | none | ethyl acetate at 50 % polymer; AIBN 0.1 wt %, 78 °C (172.4 °F) | toluene to 50 wt % polymer |
| Crosslinker | none | AlACA up to 0.55 wt % or aziridine 0.1 to 0.9 wt % on polymer | bis(2,4-dichlorobenzoyl) peroxide 1.5 wt % on dry polymer |
| Coating and cure | coated molten, sets on cooling | 60 g/m², 10 min at 110 °C (230 °F) | 50 µm polyethylene terephthalate (PET) film, 10 min at 120 °C (248 °F); coat weight not stated |
| Lab result | none reported in the source | shrinkage on PVC film 0.25 % (0.55 wt % AlACA) and 0.2 % (0.5 wt % aziridine), modified FINAT FTM 14 | reference (Antosik et al. 2023, Q2-7358 + 1.5 pph dibenzoyl peroxide, 55 % solids, 10 min at 110 °C, 45 g/m²): 180° peel 12.75 N/25 mm (FINAT FTM 1), tack 10.45 N, SAFT 192 °C (377.6 °F) |
The rubber hot melt comes from Dalley's label adhesive article in Adhesives and Sealants Industry (ASI, 2015). The formula contains no oil, and the article reports no performance row, so it serves as a composition benchmark only.
The solvent acrylic of Czech and co-workers (2022) uses azobisisobutyronitrile (AIBN) as initiator, and its crosslinker is dosed on polymer, not on formulation. The group calls 0.5 % shrinkage after 2 weeks at 70 °C (158 °F) acceptable, a lab convention rather than a standard requirement, and both crosslinked films stay below it.
The silicone formula of Antosik and co-workers (2024) replaces dibenzoyl peroxide (BPO), used in their 2023 reference system, with bis(2,4-dichlorobenzoyl) peroxide (DClBPO). The same group accepts 10 N/25 mm peel and 8 N tack as targets, again a lab convention, not a standard.
Tackifier Levels by PSA Type and End Use#
Tackifier levels depend on the PSA type and the end use, and each published level carries its own basis; the table shows them side by side.
| PSA type | Tackifier | Level (basis) | Source |
|---|---|---|---|
| Water-based PSA, paper labels | resin dispersion | 15 to 30 % (dry resin on dry polymer) | ASI 2006-04-01 |
| Water-based PSA, filmic labels | resin dispersion | 10 to 15 % (dry basis) | ASI 2006-04-01 |
| Acrylic PSA tapes | resin dispersion | 10 to 20 % (dry basis) | ASI 2006-04-01 |
| Natural rubber latex PSA | resin dispersion | 20 to 50 % (dry basis) | ASI 2006-04-01 |
| Solvent acrylic on high-density polyethylene (HDPE), one patent example | hydrocarbon resin Regalrez 6108 + plasticizer Pycal 94 | 11 + 5 parts per 100 parts acrylic polymer; 13.2 N/25 mm 180° peel at 30 cm/min | US6280557B1, Table V |
| Rubber hot melt label | C5 resin (softening point 95 °C) + liquid C5 resin | 41.6 + 27 wt % of formulation | Dalley, ASI 2015 |
| Silicone PSA | MQ resin | about 40 to 70 parts per 100 parts resin plus gum (patent range) | EP0524776A1 |
Published values with basis; not recommendations. The basis decides the comparison: a dry-basis share on polymer and a wt % of formulation never belong on one scale.
Balancing Tack, Peel and Shear in the PSA Formula#
Each formula change moves tack, peel and shear in a known direction; the table lists the main levers and their effect.
| Change | Effect |
|---|---|
| More tackifier (up to the tack window) | lower modulus at bonding rates; higher Tg, tack and peel |
| More MQ resin (silicone) | higher peel and shear, lower tack |
| More crosslinker or higher gel content | higher shear, SAFT and shrinkage resistance; lower tack and peel |
| UV crosslinking of an SBS model PSA (literature value) | SAFT rises from 68 to 90 °C; 180° peel falls from 22 to 15 N/25 mm |
| Lower adhesive Tg | Tg 30 to 70 °C below application temperature as a rule of thumb |
| More oil (SBC) | softer layer, lower viscosity |
The UV-crosslinked SBS model is the cleanest numeric case of the trade-off: one crosslinking step raised SAFT by 22 °C and cost 7 N/25 mm of peel. A formulator who needs both values higher has to change the resin or the polymer, not the cure.
Each request is passed straight to independent companies of that trade, and no company pays AdhesiveAdditives.com to be named or to receive requests; the editorial policy explains how.
Tack, Peel and Shear: The Three Properties of a PSA#
Tack is how fast a PSA wets a surface on light contact, peel is the force that strips it off, and shear is how long it holds a static load. Every PSA trades flow for tack against cohesion for shear, so no single formula maximizes all three properties at once.
PSA values compare only within one method, one test rate or temperature ramp and one load. SAFT illustrates the problem: labs run ramps of 0.5 or 1.5 °C/min with different loads and bond areas, so a SAFT value without its ramp, load and area cannot be compared with another. The same holds for peel and tack, whose values depend on dwell, panel and coat weight.
PSA Glass Transition and Modulus Targets#
The glass transition temperature of a PSA sits 30 to 70 °C below its application temperature as a rule of thumb (Baker, PSTC paper, citing Benedek 2005). Glass transition temperature in adhesives governs how soft the layer is at the moment of bonding, and the method side of Tg measurement sits under glass transition temperature in adhesives.
Optimum tack lies about 20 °C above the adhesive Tg, which is producer guidance (Eastman, ASI 2006), not a standard requirement. For tackified SBC adhesives the elastomer phase target is a Tg of -10 to 10 °C (14 to 50 °F) (Kraton, ASI 2007). Both figures are rules of thumb that set the tackifier share, never pass or fail limits.
Which Substrates Do Pressure-Sensitive Adhesives Bond?#
Pressure-sensitive adhesives bond paper, PET film, polypropylene films (BOPP, CPP), PVC film, stainless steel, glass and, with silicone or high-tack grades, low-surface-energy plastics. The seven substrate groups are listed below.
- Paper and paperboard
- Polyethylene terephthalate (PET) film
- Polypropylene films: biaxially oriented (BOPP) and cast (CPP)
- Polyvinyl chloride (PVC) film
- Stainless steel
- Glass
- Low-surface-energy (LSE) plastics such as polyethylene, with silicone or high-tack grades
Low-energy plastics resist wetting, which is why only silicone and high-tack grades are matched to them. Surface energy and wetting decide whether the adhesive spreads at all, a topic treated under surface energy and wetting. On HDPE, one example of US patent 6,280,557 B1 tackifies a 95/5 isooctyl acrylate/acrylic acid copolymer with hydrocarbon resin and plasticizer (values in the tackifier levels table).
PVC film brings two specific problems: plasticizer migrates from the film into the adhesive and softens it, and the film shrinks at elevated temperature, pulling the label edge back. A crosslinked solvent acrylic answers both, as the shrinkage results of the solvent acrylic starting formula show.
How Pressure-Sensitive Adhesives Are Applied and Cured#
A pressure-sensitive adhesive is applied with pressure at room temperature, but dried, cooled or cured on the converter's coating line: solvent and water-based grades in an oven, hot melts by cooling, UV acrylic hot melts by UV. At the user, open time does not apply, because the adhesive stays permanently tacky; the label or tape bonds whenever it is pressed down.
On the line, timing matters. A solvent acrylic mixed with an isocyanate crosslinker has a pot life of 8 to 24 h, and with an aziridine only several hours (Czech et al. 2022). Lab coat weights run from 25 g/m² for a UV acrylic hot melt on 50 µm PET to 60 g/m² for the solvent acrylic.
Solvent, Water-Based, Hot Melt and UV-Cured PSA Coatings#
Solvent, water-based, hot melt and UV-cured PSA coatings differ first in solids: a solvent acrylic is coated at about 50 % polymer, while a UV acrylic hot melt is 100 % solids. Water-based acrylics are emulsions; one published example uses BA, MMA, acrylic acid and 2-hydroxyethyl methacrylate (HEMA) at 87:10:1:2 wt % at 52 to 55 % solids (Di Lorenzo et al. 2024).
Rubber hot melts are coated molten and set on cooling, with SBC base polymers carrying the cohesion. Hot melt pressure-sensitive adhesives built on styrenic block copolymers need no solvent at all and are covered in depth under hot melt pressure-sensitive adhesives.
Silicone PSAs are coated from solvent, dried, then cured by peroxide or by platinum-catalyzed addition of vinyl to SiH groups. They need fluorosilicone release liners, because they stick to standard silicone release coatings. On paper liners for acrylic and rubber PSAs, the silicone release coat weight is 1.0 to 1.5 g/m² (0.6 to 0.9 lb/3,000 ft²) (typical product value, Momentive SilForce SL6575 data sheet, date not stated).
How Are Pressure-Sensitive Adhesives Tested?#
Pressure-sensitive adhesives are tested for peel, tack and static shear on standard panels, under ASTM D3330/D3330M-04(2025), D6195-22, D3121-25 and D3654/D3654M-06(2024) and EN ISO 29862:2024. The table maps each property to its standard, edition and status.
| Property | Standard and edition | Status | Method page |
|---|---|---|---|
| Peel adhesion (180°, 90°) | ASTM D3330/D3330M-04(2025), Methods A to F; EN ISO 29862:2024 | active; EN ISO 29862:2024 supersedes the 2019 edition; EN 1939 withdrawn 2019-06-05 | peel adhesion testing |
| Loop tack | ASTM D6195-22, Methods A and B | active | tack testing |
| Rolling ball tack | ASTM D3121-25 | active; quality control for low-tack adhesives | same page as loop tack |
| Static shear (holding power) | ASTM D3654/D3654M-06(2024), Procedures A to H; EN ISO 29863:2019 | active | static shear and SAFT testing |
| SAFT | lab ramps per paper | not comparable without ramp, load and area | same page as static shear |
| Association methods | PSTC methods (PSTC-101, PSTC-17 as cited by papers); FINAT Technical Handbook 11th edition, FTM 1, FTM 9, FTM 14 | named only | FINAT, PSTC and AFERA test methods |
ASTM D3330/D3330M states in section 5.3 that Methods A, B, C, E and F cannot compare tapes of different manufacture, because the peel force is not normalized for the stressed area. Data sheet peel values are therefore comparisons within one supplier's range. ASTM D3121-25 rolling ball tack is a quality-control method that suits low-tack adhesives and is not an end-use specification.
Regulation of Pressure-Sensitive Adhesives#
Three rule sets govern industrial PSAs: food-contact listings for labels and tapes, emission rules for the coating lines that make them, and the hazard classification of their monomers and crosslinkers. Each rule set has its own regulator and date, and none of them clears a PSA by chemistry name alone.
Food-Contact PSA Labels and Tapes Under US Rules#
21 CFR 175.125 is the US listing for PSAs that form the food-contact surface of labels and tapes, last amended by 64 FR 48291 on 1999-09-03. Paragraph (a) covers labels and tapes on poultry, dry food and processed, frozen, dried or partially dehydrated fruits and vegetables; paragraph (b) covers raw fruit and raw vegetables with a restricted list.
Numeric limits apply. Under (a)(6) the antioxidant CAS 991-84-4 is at most 1.5 wt % of the finished PSA, under (a)(9) the surfactant CAS 144093-88-9 at most 3.0 %, and 21 CFR 178.2010 caps antioxidant 1010 at 1.0 % of a 175.125 PSA. The (b)(2) list is closed: it names natural rubber, cis-1,4-polyisoprene, butyl rubber, polyisobutylene, butadiene-styrene and butadiene-acrylonitrile copolymers, terpene resins, rosins under 21 CFR 178.3870, BHA and BHT, but no petroleum hydrocarbon resin and no SIS or SBS. SBS enters food-contact PSAs through 21 CFR 177.1810 table item 1(ii), limited to closure tapes on containers of at least 160 cc (5.5 fl oz) with at most 4.03 cm² (0.625 in²) of food-exposed adhesive.
Other food labels fall under 21 CFR 175.105, which requires the label "food-packaging adhesive" and a functional barrier, dry food within good manufacturing practice, or only trace amounts at seams and edges for fatty and aqueous food. Its (c)(5) monomer list includes acrylic acid, n-butyl acrylate and 2-ethylhexyl acrylate but not isoprene, and it names polysiloxanes and benzoyl peroxide. No PSA is cleared as such; the listing and its condition of use decide. In the EU, Regulation (EC) No 1935/2004 is the framework instrument, covered with the US sections under food-contact adhesives.
Coating-Line Emissions and VOC Rules for PSA Production#
40 CFR 60 Subpart RR sets the US federal VOC limit for PSA tape and label coating lines constructed, modified or reconstructed after 1980-12-30. Such lines meet 0.20 kg VOC per kg of coating solids or a 90 % overall VOC reduction; lines emitting at or below 45 Mg (50 tons) of VOC per 12 months are exempt from the limit.
40 CFR 63 Subpart JJJJ covers web coating lines at major sources of hazardous air pollutants (HAP), including lines that coat fabric for PSA tape. Existing lines meet 5 % of organic HAP applied (a 95 % reduction), 4 % of coating materials or 20 % of coating solids; new lines meet 2 %, 1.6 % and 8 %. The subpart was last amended by 88 FR 18413 on 2023-03-29.
In Southern California, SCAQMD Rule 1168 (amended November 4, 2022; amendments proposed for a 4 December 2026 hearing) limits a pressure-sensitive adhesive primer to 785 g/L, less water and exempt compounds. Rule 1168 and the other VOC limits for industrial adhesives are compared under VOC limits for industrial adhesives.
Hazard Lines of PSA Monomers and Crosslinkers#
Residual monomers and crosslinkers carry the hazard classification of a PSA; the finished polymers and resins have no Annex VI entry under the EU CLP Regulation. The table gives the Annex VI line with index number where one exists.
| Substance | CAS (EC or list number) | Hazard line |
|---|---|---|
| 2-Ethylhexyl acrylate | 103-11-7 (EC 203-080-7) | Annex VI 607-107-00-7: Skin Irrit. 2 H315, Skin Sens. 1 H317, STOT SE 3 H335 |
| n-Butyl acrylate | 141-32-2 (EC 205-480-7) | Annex VI 607-062-00-3: Flam. Liq. 3 H226, Skin Irrit. 2 H315, Eye Irrit. 2 H319, Skin Sens. 1 H317, STOT SE 3 H335 |
| Acrylic acid | 79-10-7 (EC 201-177-9) | Annex VI 607-061-00-8: Flam. Liq. 3 H226, Acute Tox. 4 H332, H312, H302, Skin Corr. 1A H314, Aquatic Acute 1 H400 |
| Dibenzoyl peroxide | 94-36-0 (EC 202-327-6) | Annex VI 617-008-00-0 (ATP22, applicable 2026-05-01): Org. Perox. B H241, Eye Irrit. 2 H319, Skin Sens. 1 H317, Aquatic Acute 1 H400, Aquatic Chronic 1 H410 |
| Rosin (parent of rosin ester tackifiers) | 8050-09-7 (EC 232-475-7) | Annex VI 650-015-00-7: Skin Sens. 1 H317 |
| SIS, natural rubber, polyisobutylene, butyl rubber, PDMS, MQ resin, C5 resin, rosin esters | 25038-32-8, 9006-04-6, 9003-27-4, 9010-85-9, 63148-62-9, 56275-01-5, 26813-14-9, 8050-31-5 | No Annex VI entry |
| Trimethylolpropane tris(2-methyl-1-aziridinepropionate), aluminum acetylacetonate | 64265-57-2 (EC 264-763-3), 13963-57-0 (EC 237-741-6) | No Annex VI entry |
Three of the four Annex VI substances carry Skin Sens. 1 H317, and so does the parent of rosin ester tackifiers: Rosin (CAS 8050-09-7) carries CLP Annex VI 650-015-00-7 Skin Sens. 1 H317. A PSA formula containing residual acrylic monomer or peroxide is classified as a mixture, so the product safety data sheet, not the polymer, decides the label.
How to Choose a Pressure-Sensitive Adhesive#
Choose a pressure-sensitive adhesive by service temperature and substrate first, then by removability, food-contact status and the coating process your line runs.
Acrylic vs rubber pressure-sensitive adhesives is the first decision for most labels and tapes, set out in detail under acrylic vs rubber pressure-sensitive adhesives. The table matches requirements to PSA types with the evidence behind each match.
| Requirement | PSA type | Evidence |
|---|---|---|
| High service temperature | silicone (peroxide cured) | SAFT 192 °C (377.6 °F), lab value (Antosik et al. 2023) |
| High shear at elevated temperature, no solvent | UV acrylic hot melt | SAFT above 135 °C crosslinked against 109 °C uncrosslinked (PSTC-17 as run), typical product value of a commercial artimelt high-shear grade reported in a 2024 study |
| Low-surface-energy plastics | tackified acrylic or silicone | 13.2 N/25 mm 180° peel on HDPE, one example of US6280557B1 |
| PVC film labels | crosslinked solvent acrylic | shrinkage 0.2 to 0.25 % with crosslinker (lab, Czech et al. 2022) |
| Clean removal or repositioning | removable acrylic (high gel content, microspheres) | gel 92 % (high crosslink) against 42 %; microspheres 10 to 250 µm, Tg -70 °C (-94 °F) |
| Labels on raw fruit and vegetables (US) | rubber-based PSA built only from the 21 CFR 175.125(b)(2) list | closed list names natural rubber, butyl rubber, polyisobutylene; no SIS or SBS |
Each request is passed straight to independent companies of that trade, and no company pays AdhesiveAdditives.com to be named or to receive requests; the editorial policy explains how.
Limits of Pressure-Sensitive Adhesives#
Pressure-sensitive adhesives have six recurring limits, each traced to the formula or the construction.
- Residue and ghosting, when the adhesive is too soft or under-crosslinked
- Plasticizer migration from PVC film into the adhesive
- Shrinkage of PVC film that pulls back label edges
- Low cohesion from incomplete cure on the coating line
- Anchorage failure between adhesive and backing
- Liner release problems, including silicone PSAs on standard silicone liners
Most of these limits trace back to crosslink density or to the backing and liner, so they are solved on the coating line rather than by the user.
Types of Pressure-Sensitive Adhesive: Acrylic, Rubber, Silicone and Removable#
Pressure-sensitive adhesives fall into acrylic, rubber-based and silicone chemistries, and each can be designed as a permanent, removable or repositionable grade. The table compares the four types by base polymer, source of cohesion and use.
| Type | Base polymer | Cohesion from | Typical uses |
|---|---|---|---|
| Acrylic pressure-sensitive adhesives | low-Tg acrylic copolymer (BA or 2-ethylhexyl acrylate, MMA, acrylic acid) as emulsion, solvent or UV acrylic hot melt | molecular weight, gel content, carboxyl crosslinking (chelate, aziridine, isocyanate) or UV after coating | labels, tapes, PVC film |
| Rubber-based PSAs | tackified natural rubber, SBC, PIB or butyl rubber from solvent, hot melt or latex | elastomer network; natural rubber may be crosslinked for heat resistance | labels, packaging tapes, low-temperature and rough surfaces |
| Silicone pressure-sensitive adhesives | PDMS gum plus MQ resin in solvent | peroxide or platinum addition cure | high-temperature tapes, LSE surfaces |
| Removable, repositionable and permanent PSAs | acrylic designed for low peel and high cohesion | gel content, crosslinker chemistry, hard monomer share; microspheres for repositioning | removable labels, graphics |
Removability is a design target, not a fourth chemistry. A removable grade keeps peel low and cohesion high relative to adhesion, so it fails cleanly at the substrate after aging; repositionable grades add microspheres that limit the contact area.
Pressure-Sensitive Adhesives in Industry and Research#
Pressure-sensitive adhesives serve three industrial uses, labels, tapes and medical devices, while research targets their cure, crosslinking and shrinkage on film. They sit alongside hot melt, water-based and reactive systems among the types of adhesives by chemistry, as the family that needs no setting step at the user.
Where Are Pressure-Sensitive Adhesives Used?#
Pressure-sensitive adhesives are used in three industrial application groups, listed below.
- Label adhesives for paper and filmic labels on packaging
- Adhesives for tapes on paper, film, foil, nonwoven and cloth backings
- Medical device adhesives for skin-contact tapes and device fixation
Flooring installation adhesives sold as pressure-sensitive grades are a construction topic outside the scope of this site.
What Should a PSA Supplier State on the Data Sheet?#
A PSA supplier should state each value on the data sheet as a typical product value with its method, dwell, test panel and coat weight. Without those conditions a peel or SAFT number cannot be compared, because ASTM D3330/D3330M itself rules out comparisons across manufacturers for most methods.
The six data sheet fields that make adhesive manufacturers and suppliers comparable are listed below; request the same fields from every source, and see adhesive manufacturers and suppliers for how to compare and source them.
- Peel adhesion with method, panel, dwell and coat weight
- Loop tack with method
- Static shear with load, area and temperature
- SAFT with ramp rate and load
- Service and application temperature range
- Regulatory statements with the exact section, such as 21 CFR 175.125(a) or (b)
From the 1955 PSTC Manual to Current PSA Research#
The Pressure Sensitive Tape Council was founded in 1953 and published its first test manual in 1955 with 8 methods, among them 180° peel and shear holding. The council reviews its methods annually, and papers still cite them by number, such as PSTC-101 for peel.
The reference work of the field is the Handbook of Pressure-Sensitive Adhesives and Products by Benedek and Feldstein, in 3 volumes (Taylor & Francis listing dated 2019). Current open-access research by the Czech and Antosik groups targets crosslinker choice, peroxide cure and shrinkage on PVC film.