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EP-4735549-A1 - HOT MELT PRESSURE-SENSITIVE ADHESIVE

EP4735549A1EP 4735549 A1EP4735549 A1EP 4735549A1EP-4735549-A1

Abstract

The present invention relates to a hot melt pressure-sensitive adhesive composition comprising: – a styrene block polymeric component; – a mixture of tackifying resins, said mixture comprising: o a) a rosin-based resin; o b) a rosin ester resin different from tackifying resin a); o c) a terpene-based resin.

Inventors

  • BEYER, Marie
  • RAFAITIN, Amandine

Assignees

  • Bostik SA

Dates

Publication Date
20260506
Application Date
20240624

Claims (20)

  1. 1. Hot melt pressure-sensitive adhesive composition comprising: - a styrene block polymeric component; - a mixture of tackifying resins, said mixture comprising: o a) a rosin-based resin ; o b) a rosin ester resin different from tackifying resin a); o c) a terpene-based resin.
  2. 2. Hot melt pressure-sensitive adhesive composition according to claim 1 , characterized in that it has a glass transition temperature lower than 5°C, more preferably lower than 2°C.
  3. 3. Hot melt pressure-sensitive adhesive composition according to anyone of claim 1 or 2, wherein the styrene block polymeric component has an average styrene content of from 5% by weight to 55% by weight, more preferably from 15% by weight to 45% by weight.
  4. 4. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 3, wherein the styrene block copolymer is selected from the group consisting of SB, SI, SEB, SEP, SBBS, SBS, SEBS, SEPS, SEEPS, SIBS, SIS, random-block SBR, random-block SIR and mixtures thereof.
  5. 5. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 4, wherein the styrene block polymeric component comprises : at least one linear triblock SIS copolymer; at least one diblock SI copolymer; optionally at least one linear triblock SBS copolymer; and optionally at least one diblock SB copolymer.
  6. 6. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 5, wherein it comprises from 5 % to 40 % by weight, preferably from 10% to 35 % by weight, even more preferably from 15 % to 35 % by weight of styrene block polymeric component, based on the total weight of the hot melt pressure-sensitive adhesive composition.
  7. 7. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 6, wherein the rosin-based resin a) is at least partially hydrogenated, preferably it is fully hydrogenated.
  8. 8. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 7, wherein the rosin-based resin a) is not a rosin ester.
  9. 9. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 8, wherein the rosin ester b) is selected from the group consisting of glycerol esters of pale wood rosin, glycerol esters of hydrogenated rosin, glycerol esters of polymerized rosin, pentaerythritol esters of pale wood rosin, pentaerythritol esters of hydrogenated rosin, pentaerythritol esters of tall oil rosin and phenolic modified pentaerythritol esters of rosin, their hydrogenated versions, and mixtures thereof, more preferably the rosin ester b) is selected from pentaerythritol rosin ester of tall oil rosin.
  10. 10. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 9, wherein the rosin ester b) has a Ring and Ball softening point lower than 110°C.
  11. 11. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 10, wherein the terpene-based resin c) is selected from polyterperne homopolymers, their hydrogenated versions, and mixtures thereof.
  12. 12. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 11 , characterized in that it comprises: from 8% to 30% by weight of rosin-based resin a); from 10% to 40% by weight of rosin ester resin b); from 8% to 30% by weight of terpene-based resin c), based on the total weight of the hot melt pressure-sensitive adhesive composition.
  13. 13. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 12, wherein it has a total styrene content higher ranging from 5% to 20%, more preferably ranging from 5% to 15%, and even more preferably ranging from 6% to 11%.
  14. 14. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 13, wherein it does not comprise petroleum tackifier.
  15. 15. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 14, wherein it comprises a biobased plasticizer.
  16. 16. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 15, wherein the biobased plasticizer is selected from the group consisting of animal fat, vegetable oil, their derivatives thereof, lactic acid derivatives, modified versions thereof, fatty acid derivatives, diene homopolymers, and mixtures thereof, more preferably the biobased plasticizer is selected from vegetable oil and their derivatives thereof, and fatty acid derivatives.
  17. 17. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 16, wherein the biobased plasticizer has a weight average molecular weight higher than or equal to 2 500 g/mol, more preferably higher than or equal to 3 000 g/mol, and even more preferably ranges from 3 000 g/mol to 12 000 g/mol.
  18. 18. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 17, characterized in that it has an average peel strength higher than or equal to 10 N/25 mm with an adhesive coating weight of 20 g/m 2 on stainless, and/or an average peel strength higher than or equal to 5 N/25 mm with an adhesive coating weight of 20 g/m 2 on cardboard.
  19. 19. Hot melt pressure-sensitive adhesive composition according to anyone of claims 1 to 18, characterized in that it has a static shear at 23°C higher than 1 000 minutes with an adhesive coating weight of 20 g/m 2 .
  20. 20. Multilayer system comprising: - an adhesive layer (A) consisting of the HMPSA composition as disclosed in anyone of claims 1 to 19; - a support layer (B) adjacent to the adhesive layer (A); and - a nonstick protective layer (C), adjacent to the adhesive layer (A).

Description

Hot melt pressure-sensitive adhesive TECHNICAL FIELD The present invention relates to hot melt adhesive comprising a mixture of tackifying resins, and their uses. TECHNICAL BACKGROUND Pressure-sensitive adhesives (PSAs) are substances which give the support layer which is coated therewith an immediate tack at ambient temperature (23°C). This immediate tack enables the instantaneous adhesion of said self-adhesive support to all types of substrates, under the effect of a gentle and brief pressure. PSAs are widely used for the manufacture of self-adhesive labels which are attached to articles (for example packaging) for the purpose of presenting information (such as barcode, name, price) and/or for decorative purposes. PSAs are also employed in the manufacture of self-adhesive tapes of varied uses. Mention may be made, for example, besides the transparent adhesive tape widely used in daily life, of the forming and the assembling of cardboard packagings; the protection of surfaces for painting operations, in the building industry; the maintenance of electric cables in the transportation industry: the adhesive bonding of fitted carpets by double-sided adhesive tapes. PSAs are generally applied, by continuous coating processes carried out by industrial machines known as "coaters", over the whole of the surface of a large-sized support layer, where appropriate which is printable, in an amount (generally expressed in g/m2) denoted hereinbelow by the term "weight per unit area". The support layer generally consists of paper or of film of a polymeric material having one or more layers. The layer of self-adhesive composition which covers the support layer is itself covered with a protective nonstick layer (often known as a release liner), which often consists of a silicone film. The multilayer system obtained is generally packaged by winding in the form of large reels (or rolls) up to 2 m in width and 1 m in diameter, which can be stored and transported, such packaging often being referred to by the expression "roll stock". This multilayer system can subsequently be converted into self-adhesive labels which can be applied by a label manufacturer referred to as a “converter”, by means of conversion processes which include the printing of desired informative and/or decorative elements onto the printable face of the support layer, followed by cutting to the desired shape and sizes. The protective nonstick layer can be easily removed without modifying the adhesive layer, which remains attached to the printable support layer. After separation from its nonstick protective layer, the label is applied in general at a temperature close to ambient temperature (23°C) to the article (for example the packaging) to be coated, either manually or with the aid of labelling machines on automated packaging lines. This multilayer system can also be converted into self-adhesive tapes by cutting and packaging as rolls of predetermined width and length. PSAs advantageously allow, due to their high ambient-temperature tack, rapid holding or attachment of the self-adhesive label and/or tape to the substrate (or article) to be coated (for example, as regards labels, on packagings, or else, as regards tapes, on packing boards to be formed), suitable for obtaining high industrial production rates. Hot-melt adhesives or hot melts (HMs) are substances that are solid at ambient temperature and contain neither water nor solvent. They are applied in the melt state and solidify on cooling, thus forming a joint which, due to its adhesive strength, attaches the substrates to be assembled. Certain hot melts are formulated in such a way as to give the support coated therewith a relatively hard and tack-free character. Other hot melts provide the support with a relatively soft character and a high tack; these are PSAs which are widely used for the manufacture of self-adhesive articles (for example self-adhesive labels). The corresponding adhesives are denoted by the designation "hot-melt pressure-sensitive adhesives" (or HMPSA). HMPSA are thus a different category than hot melt. HM. They therefore also make it possible, owing to their adhesive strength, to firmly attach the label or the tape to the desired substrate, whether it is for example packaging to be labeled or board to be assembled. Refrigerated and cold food labels may be primarily intended to communicate important product messaging, nutrition information and branding information, but they also help products sell. Indeed, most of the consumers will try a new product if a packaging catches their eyes. Impressions take about seven seconds, making subsequent judgments based on quick information. Thus, a label falling off from a packaging will negatively impact the consumers. In beverage labeling, bottles often move from place to place, like a cold refrigerator to a warm car, creating condensation and affecting label performance. In refrigerated labeling, if outdoor temperatures are hot and humid,