Process of manufacturing a pressure sensitive adhesive having a low VOC characteristics

Patent metadata

Field	Value
Publication number	US-11905438-B2
Application number	US-201917252348-A
Country	US
Kind code	B2
Filing date	Jun 20, 2019
Priority date	Jun 22, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

The present disclosure relates to a process of manufacturing a pressure sensitive adhesive, comprising the steps of: a) providing a hot melt mixing apparatus comprising a reaction chamber; b) providing a hot melt processable pressure sensitive adhesive composition comprising: (1) a (meth)acrylate copolymer component comprising: i. C1-C32 (meth)acrylic acid ester monomer units; ii. optionally, ethylenically unsaturated monomer units having functional groups selected from the group consisting of acid, hydroxyl, acid anhydride, epoxide, amine, amide groups, and any combinations thereof; and iii. optionally, further ethylenically unsaturated monomer units which are copolymerizable with monomer units (i) and/or (ii); and (2) a crosslinking system selected from the group consisting of thermal crosslinking systems, actinic radiation crosslinking systems, and any combinations thereof; (3) optionally, at least one expandable microsphere; and (4) optionally, at least one pigment; c) providing a polymeric resin; d) subjecting the polymeric resin to a heating step (thereby at least partly remove low Volatile Organic Compounds (VOC) from the polymeric resin) thereby forming a cleaned polymeric resin; e) incorporating the cleaned polymeric resin and the hot melt processable pressure sensitive adhesive composition in the reaction chamber of the hot melt mixing apparatus; −57-f) mixing the hot melt processable pressure sensitive adhesive composition and the cleaned polymeric resin in the hot melt mixing apparatus thereby forming a hot melt blend; g) removing the hot melt blend from the hot melt mixing apparatus; and h) optionally, crosslinking the hot melt blend.

First claim

The invention claimed is:

1. A process of manufacturing a pressure sensitive adhesive, comprising the steps of:
a) providing a hot melt mixing apparatus comprising a reaction chamber;
b) providing a hot melt processable pressure sensitive adhesive composition comprising:
(1) a (meth)acrylate copolymer component comprising:
i. one or more C 1 -C 32 (meth)acrylic acid ester monomer units;
ii. one or more ethylenically unsaturated monomer units having functional groups selected from the group consisting of acid, hydroxyl, acid anhydride, epoxide, amine, amide groups, and any combinations thereof; and
iii. one or more ethylenically unsaturated monomer units which are copolymerizable with monomer units (i) and/or (ii); and

(2) a crosslinking system selected from the group consisting of thermal crosslinking systems, actinic radiation crosslinking systems, and a combination thereof;
the hot melt processable pressure sensitive adhesive composition
(3) optionally further comprising at least one of expandable microspheres; and
(4) at least one pigment;

c) providing a polymeric resin;
d) subjecting the polymeric resin to a heating step (thereby at least partly remove low Volatile Organic Compounds (VOC) from the polymeric resin) thereby forming a (pre-)cleaned polymeric resin;
e) incorporating the (pre-)cleaned polymeric resin and the hot melt processable pressure sensitive adhesive composition in the reaction chamber of the hot melt mixing apparatus;
f) mixing the hot melt processable pressure sensitive adhesive composition and the (pre-) cleaned polymeric resin in the hot melt mixing apparatus thereby forming a hot melt blend;
g) removing the hot melt blend from the hot melt mixing apparatus; and
h) crosslinking the hot melt blend.

2. A process according to claim 1 , wherein the hot melt blend has a Volatile Organic Compound (VOC) value of less than 1500 ppm when measured by thermal desorption analysis according to test method VDA278.

3. A process according to claim 1 , wherein the hot melt mixing apparatus is selected from the group of single- and multi-screw extruders.

4. A process according to claim 1 , wherein the crosslinking system is a thermal crosslinking system comprising a thermal crosslinker and optionally, a crosslinking accelerator.

5. A process according to claim 1 , wherein the polymeric resin is selected from the group consisting of tackifying resins, plasticizing resins, and any combinations or mixtures thereof.

6. A process according to claim 1 , wherein the hot melt processable pressure sensitive adhesive composition comprises:
a) from 20 wt % to 80 wt % of the (meth)acrylate (co)polymer component, based on the weight of the hot melt processable pressure sensitive adhesive composition;
b) from 0.1 wt % to 10 wt % of a crosslinking agent, based on the weight of the hot melt processable pressure sensitive adhesive composition;
c) from 20 wt % to 70 wt % of the polymeric resin, based on the weight of the hot melt processable pressure sensitive adhesive composition;
the hot melt processable pressure sensitive adhesive composition
d) optionally further comprising at least one of from 1 wt % to 20 wt % of the expandable microspheres, based on the weight of the hot melt processable pressure sensitive adhesive composition; and
e) from 0.5 wt % to 20 wt % of the at least one pigment, based on the weight of the hot melt processable pressure sensitive adhesive composition.

7. A process according to claim 1 , wherein the step of subjecting the polymeric resin to a heating step (thermal treatment) is performed by subjecting the polymeric resin to any of thermal heating, radiation heating, convection heating, induction heating, ultrasonic vibration heating, and any combinations thereof.

8. A process according to claim 1 , wherein the step of subjecting the polymeric resin to a heating step is performed in a feeding equipment for polymeric resins associated with the hot melt mixing apparatus, in particular a multi- or single screw extruder or a planetary roller extruder.

9. A process according to claim 1 , wherein the step of subjecting the polymeric resin to a heating step is performed in a Wiped Film Evaporator.

10. A crosslinked pressure sensitive adhesive which is obtained by a process according to claim 1 , wherein the crosslinked pressure sensitive adhesive has a Volatile Organic Compound (VOC) value of less the 300 ppm when measured by thermal desorption analysis according to test method VDA278.

Assignees

• 3M Innovative Properties Company

Inventors

• Matzeit Niklas M
• Bieber Pierre R
• Stegmaier Petra M
• Klünker Eike H
• Iarikov Dmitri D
• Imsande Jeffrey M
• Cheng Shijing
• Craton Michele A
• Clements George J

Classifications

• C09J133/08 Primary

  Homopolymers or copolymers of acrylic acid esters · CPC title

• B29C48/08

  flexible, e.g. films · CPC title

• B29C48/288

  in solid form, e.g. powder or granules · CPC title

• B29C48/40

  using two or more parallel screws {or at least two parallel non-intermeshing screws}, e.g. twin screw extruders · CPC title

• C08F220/1808

  C8-(meth)acrylate, e.g. isooctyl (meth)acrylate or 2-ethylhexyl (meth)acrylate · CPC title