JP2014148680A - Water-based emulsion type adhesive composition for wrapping processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environment friendly water-based emulsion type adhesive composition which has workability enabling use in a wrapping line which uses a solvent-based adhesive, and has the same performance as the solvent-based adhesive.SOLUTION: The water-based emulsion type adhesive composition for wrapping processing is obtained by performing emulsion polymerization of unsaturated monomers including an alkyl (meth)acrylate (A) and vinyl acetate as another unsaturated monomer (C) in the presence of a tackifier (D) in an amount of 0.5-10 pts.mass based on 100 pts.mass of the unsaturated monomers. Further, a carboxyl group-containing unsaturated monomer (B) is preferably contained in an amount of 3-15 pts.mass in the unsaturated monomers. Furthermore, the another unsaturated monomer (C) is preferably contained in an amount of 2-11 pts.mass in the unsaturated monomers.

Description

  The present invention relates to an adhesive composition used for wrapping processing such as a profile.

  Currently, a wide range of wrapping processes for wrapping a decorative sheet to give a design to a deformed material (profile) with curved surfaces and irregularities on the surface used for building interior materials such as window frames, door frames and baseboards Has been done. Conventionally, solvent-based two-component urethane resins have been used as wrapping adhesives. However, in recent years, from the viewpoint of environmental problems, sick house syndrome, and occupational health and safety, the amount of highly volatile organic solvents such as toluene and xylene used as adhesive components has decreased, and the transition to aqueous systems has progressed. Therefore, a silylated urethane-based aqueous composition containing a polymer having an alkoxysilyl group at its terminal (see Patent Document 1), a synthetic rubber latex, a urethane resin emulsion, and an aqueous adhesive composition containing an acrylic resin emulsion ( A water-based adhesive composition (see Patent Document 3) containing an ethylene-vinyl acetate copolymer emulsion, an anionic urethane resin emulsion and a water-soluble urethane resin has been developed. An aqueous adhesive having the same workability and solvent-based adhesive that can be used in the agent use line has not been developed yet.

  Note that hot melt adhesives are also being studied as an alternative to solvent-based adhesives. However, hot-melt adhesive is used to wrap wooden sheets (plywood, MDF, particle board) having a cross-section with a decorative sheet, and hot-melt adhesive different from the manufacturing equipment using solvent-based adhesive. It is necessary to introduce a new production facility using an adhesive. Therefore, there is a problem that the manufacturing cost increases.

  By the way, as a prior art regarding the tackifier-containing emulsion, a method for producing a rosin compound-containing emulsion has been disclosed (for example, see Patent Documents 4 to 10). It was not that high adhesiveness and heat-resistant creep properties were exhibited.

JP 2004-300402 A JP 2008-266399 A Japanese Patent Laid-Open No. 2004-197048 Japanese Patent Laid-Open No. 2-80482 Japanese Patent Laid-Open No. 6-264041 JP-A-11-189610 JP 2002-97213 A JP 2003-96420 A JP-A-2005-220295 JP 2006-509890 A

  An object of the present invention is to provide a water-based emulsion adhesive composition for lapping processing which is easy on the environment and has the same performance as a solvent-based adhesive, which can be used on a solvent-based adhesive-using wrapping line. Is.

  As a result of studies to solve the above-mentioned problems, the present inventors have found that an aqueous emulsion adhesive obtained by emulsion polymerization in the presence of a petroleum resin-based and natural resin-based tackifier is the above-mentioned problem. As a result, the present invention has been completed. That is, the present invention includes (meth) acrylic acid ester (A), carboxyl group-containing unsaturated monomer (B), and other unsaturated monomer (C). ), A carboxyl group-containing unsaturated monomer (B) and another unsaturated monomer (C), the total amount of 100 parts by mass, the tackifier (D) 0.5-10 parts by mass The present invention provides an aqueous emulsion adhesive for wrapping processing having a glass transition temperature of -20 to -60 ° C obtained by emulsion polymerization in the presence of (petroleum resin-based and natural resin-based tackifiers).

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a water-based emulsion adhesive for lapping that imparts workability that can be used in a solvent-based adhesive-using wrapping line and is excellent in adhesion and heat-resistant creep resistance.

  Examples of the (meth) acrylic acid alkyl ester (A) used for producing the aqueous emulsion adhesive composition according to the present invention include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, Acrylic acid esters such as isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl acrylate, methyl methacrylate, n-butyl methacrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n -Methacrylates such as octyl methacrylate and isooctyl methacrylate, 2-hydroxylethyl (meth) acrylate, 2-hydro Shimechiru (meth) acrylate, 2-hydroxypropyl (meth) hydroxyl group-containing monomers such as acrylate. One or two or more may be used. Of these, methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferable in terms of imparting excellent adhesiveness to the adhesive composition.

  Of the total amount of unsaturated monomers used for the polymerization of the aqueous emulsion adhesive composition, 100 parts by weight of the (meth) acrylic acid alkyl ester (A) is preferably 75 to 95 parts by weight, and 80 to 90 parts by weight. More preferably, it is a part. When the amount is less than 75 parts by mass, the adhesiveness of the adhesive composition is lowered, so that workability is deteriorated. When the amount is more than 95 parts by mass, the heat resistant creep property tends to be lowered.

  Examples of the carboxyl group-containing unsaturated monomer (B) used for producing the aqueous emulsion adhesive composition according to the present invention include acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, crotonic acid, β- It is a monomer containing a carboxyl group such as carboxyethyl acrylate. Of these, acrylic acid and methacrylic acid are preferable because they give excellent heat-resistant creep resistance to the adhesive composition.

  In 100 parts by mass of the total amount of unsaturated monomers used for the polymerization of the aqueous emulsion adhesive composition, the carboxyl group-containing unsaturated monomer (B) is preferably 3 to 15 parts by mass, More preferably, it is 13 parts by mass. When the amount is less than 3 parts by mass, the heat resistant creep resistance is lowered. When the amount is more than 15 parts by mass, the water resistance tends to be lowered.

  The aqueous emulsion type adhesive composition further comprises unsaturated monomers other than (meth) acrylic acid alkyl ester (A) and carboxyl group-containing unsaturated monomer (B) (other unsaturated monomers (C )) Can also be copolymerized. Other unsaturated monomers (C) used for producing the aqueous emulsion adhesive composition according to the present invention include vinyl esters such as vinyl acetate, vinyl versatate, vinyl propionate, and vinyl pivalate. Amide group-containing monomers such as acrylamide, methacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, styrene, styrene derivatives, diene monomers such as ethylene, acrylonitrile, butadiene, hexadiene, diallyl phthalate, divinyl And monomers having two or more unsaturated double bonds such as benzene and triallyl cyanurate. Other unsaturated monomers (C) can be used alone or in combination. Of these, vinyl acetate and styrene are preferable in terms of improving the cohesive strength of the adhesive composition.

  Other unsaturated monomer (C) (for example, vinyl acetate) is 2 to 11 parts by mass in 100 parts by mass of the total amount of unsaturated monomers used for the polymerization of the aqueous emulsion adhesive composition. Is preferable, and it is more preferable that it is 4-9 mass parts. When the amount is less than 2 parts by mass, the heat resistant creep resistance is lowered, and when the amount is more than 11 parts by mass, the adhesiveness tends to be lowered.

  In the present invention, it is also possible to use a chain transfer agent. Examples of chain transfer agents include mercaptans such as lauryl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, β-mercaptopropionic acid, 2-ethylhexyl thioglycolate, and alcohols such as methanol and isopropyl alcohol. Or it can be used in combination. The amount of the chain transfer agent used is preferably 0 to 4 parts by mass, and 0 to 2 parts by mass with respect to 100 parts by mass of the total amount of unsaturated monomers used for the polymerization of the aqueous emulsion adhesive composition. It is more preferable that When the amount is more than 4 parts by mass, the cohesive force of the adhesive composition is lowered and the heat resistant creep property tends to be lowered.

  As the tackifier (D), petroleum resin-based (polymer of C5 / C9 fraction or copolymer thereof) tackifier, rosin-based, rosin derivative-based (for example, rosin ester, polymerized rosin), Examples thereof include natural resin tackifiers such as terpenes and terpene derivatives (for example, terpene phenol resins and rosin-modified terpene phenol resins). In the present invention, an appropriate amount of the tackifier (D) is dissolved in an unsaturated monomer to form an emulsion, and emulsion polymerization is performed, thereby aggregating the adhesive while maintaining high initial adhesiveness. It has been found that the strength can be improved and heat resistance can be imparted to the adhesive. In particular, a petroleum resin tackifier is preferable in that it has high initial adhesiveness.

  The use amount of the tackifier (D) is 100 mass of the total amount of (meth) acrylic acid ester (A), carboxyl group-containing unsaturated monomer (B), and other unsaturated monomer (C). 0.5 to 10 parts by mass, preferably 2 to 7 parts by mass with respect to parts. When the amount of tackifier used is less than 0.5 parts by mass, sufficient cohesive force cannot be obtained. Further, when the amount of tackifier used is more than 10 parts by mass, a stable aqueous emulsion adhesive composition cannot be obtained.

  The aqueous emulsion adhesive composition of the present invention can be produced by an ordinary emulsion polymerization method using an emulsifier and a catalyst. As the emulsifier used for the polymerization, commercially available anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers and reactive emulsifiers can be used. Moreover, these emulsifiers can be used individually or in combination of 2 or more types.

  Examples of such emulsifiers include polyoxyethylene alkyl ether and derivatives thereof, polyoxyethylene alkyl phenyl ether and derivatives thereof, nonionic surfactants such as polyoxyethylene propylene ether and derivatives thereof, alkyl sulfate salts, fatty acid salts, Anionic surfactants such as alkylbenzene sulfonates, polyoxyethylene alkyl ether salts, polyoxyethylene alkyl allyl ether salts, and the like, and two ethylenic carbon atoms having a sulfonic acid group, a sulfonate group, a sulfate ester group, or an ethyleneoxy group. Examples thereof include reactive emulsifiers such as compounds having a heavy bond and compounds selected from the group consisting of mixtures thereof.

  Catalysts used for the polymerization are radical generating catalysts such as ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, azobisisobutyronitrile, t-butyl hydroperoxide, etc. Accordingly, these catalysts may be used in combination with a reducing agent such as sodium bisulfite, Rongalite, sodium tartrate, sodium ascorbate.

  Moreover, various additives can be mix | blended as needed. Additives include cellulose derivatives such as polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose and starch, natural and synthetic water-soluble polymers such as casein and polyacrylamide, dibutyl phthalate, dioctiphthalate, texanol, DBE (Dibasic Ester) Plasticizers and film-forming aids such as, pigments such as titanium oxide, inorganic substances such as calcium carbonate and clay, various antifoaming agents, preservatives and the like are appropriately used.

  The glass transition temperature (hereinafter referred to as Tg) of the aqueous emulsion adhesive composition of the present invention is −20 to −60 ° C., preferably −30 to −50 ° C. When Tg is higher than −20 ° C., the initial adhesiveness is lowered, and when Tg is lower than −60 ° C., the cohesive strength of the resin is lowered, which is not preferable.

  The gel fraction of the aqueous emulsion adhesive composition of the present invention is preferably 55 to 85%, and more preferably 60 to 80%. When the gel fraction is lower than 55%, the cohesive force of the adhesive composition is low, so the heat-resistant creep resistance is lowered. When the gel fraction is higher than 85%, the adhesiveness is lowered and workability tends to be worsened. is there. Here, the gel fraction refers to a value obtained by a gel fraction measurement method described later. In order to adjust the gel fraction within this range, a predetermined amount and a predetermined type of tackifier are used, or a predetermined amount of chain transfer agent is used.

  The viscosity at 23 ° C. of the aqueous emulsion type adhesive composition of the present invention is preferably 4000 to 16000 mPa · s, and more preferably 8000 to 12000 mPa · s. When the viscosity is less than 4000 mPa · s, there is a problem that the adhesive composition droops when applied to a decorative sheet, and when the viscosity is more than 16000 mPa · s, it is difficult to adjust the coating amount and workability tends to be poor. It is in.

  The aqueous emulsion type adhesive composition of the present invention is suitably used for wrapping processing in which a decorative sheet (especially made of polyolefin or PET) is wound around a profile.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not restrict | limited to these Examples. In the examples,% and part are based on mass.

Example 1
In a container having a stirrer, a thermometer, a reflux condenser, and a dropping funnel, 20 parts of ion-exchanged water was charged and raised to 80 ° C. On the other hand, 26 parts of n-butyl acrylate, 16 parts of methyl methacrylate, 44 parts of 2-ethylhexyl acrylate, 6 parts of vinyl acetate, 8 parts of methacrylic acid, alkone P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Industries, Ltd. ) 3 parts, 21 parts water, 1 part Adekaria soap SR-10 (ether sulfate type, manufactured by ADEKA Corporation), 3 parts Elemiol RS-3000 (reactive emulsifier, manufactured by Sanyo Chemical Industries, Ltd.), New Coal 293 ( 3 parts of a sulfonic acid type anionic emulsifier (manufactured by Nippon Emulsifier Co., Ltd.) was emulsified with a homomixer to prepare a mixed emulsion. In the container, 0.09 part of sodium bisulfite and 0.03 part of ammonium persulfate were added, and emulsion polymerization was started. The polymerization was performed by adding dropwise the mixed emulsion and 7.1 parts of a 4% aqueous solution of ammonium persulfate over 4.5 hours. During this time, the temperature in the container was kept at 80 ° C. After completion of the dropping, the inside of the container was kept at 80 ° C. for 1 hour for aging. Then, it cooled to 30 degrees C or less, and added 16 parts of DBE. The obtained aqueous emulsion adhesive composition had a nonvolatile content of 57.8% and a viscosity of 10600 mPa · s.

(Example 2)
In Example 1, polymerization was performed in the same manner as in Example 1 except that the amount of Alcon P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Industries, Ltd.) was changed to 6 parts, and an aqueous emulsion type An adhesive composition was obtained. The obtained aqueous emulsion adhesive composition had a non-volatile content of 58.0% and a viscosity of 11000 mPa · s.

(Example 3)
In Example 1, the same as Example 1 except that Alcon P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Co., Ltd.) was changed to Clearon K-110 (terpene, manufactured by Yashara Chemical Co., Ltd.). Polymerization was carried out to obtain an aqueous emulsion adhesive composition. The obtained aqueous emulsion adhesive composition had a nonvolatile content of 57.9% and a viscosity of 10,000 mPa · s.

(Example 4)
Example 1 except that Alcon P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Industries, Ltd.) was changed to Pencel D-125 (rosin, manufactured by Arakawa Chemical Industries, Ltd.) in Example 1. Polymerization was carried out in the same manner as above to obtain an aqueous emulsion type adhesive composition. The obtained aqueous emulsion adhesive composition had a non-volatile content of 58.3% and a viscosity of 10,000 mPa · s.

(Example 5)
In Example 1, polymerization was carried out in the same manner as in Example 1 except that 0.05 part of dodecyl mercaptan was added as a chain transfer agent to the mixed emulsion to perform polymerization, and an aqueous emulsion type adhesive composition was obtained. . The obtained aqueous emulsion adhesive composition had a non-volatile content of 58.7% and a viscosity of 10,000 mPa · s.

(Comparative Example 1)
In Example 1, polymerization was performed in the same manner as in Example 1 except that Alcon P-125, which is a tackifier, was not used, to obtain an aqueous emulsion adhesive composition. The obtained aqueous emulsion adhesive composition had a non-volatile content of 57.0% and a viscosity of 10,000 mPa · s.

(Comparative Example 2)
In Example 1, polymerization was performed in the same manner as in Example 1 except that Alcon P-125, which is a tackifier, was not used. Furthermore, Nanolet R1050 (terpene phenol copolymer emulsion, solid content 53%) 5.7 parts of Yasuhara Chemical Co., Ltd.) was added later to obtain an aqueous emulsion type adhesive composition. The obtained aqueous emulsion adhesive composition had a non-volatile content of 56.8% and a viscosity of 10,000 mPa · s.

(Comparative Example 3)
In Example 1, polymerization was carried out in the same manner as in Example 1 except that the amount of Alcon P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Industries, Ltd.) was changed to 0.3 part, and water-based An emulsion-type adhesive composition was obtained. The obtained aqueous emulsion adhesive composition had a non-volatile content of 57.2% and a viscosity of 11000 mPa · s.

(Comparative Example 4)
In Example 1, polymerization was performed in the same manner as in Example 1 except that the amount of Alcon P-125 (alicyclic saturated hydrocarbon resin, manufactured by Arakawa Chemical Industries, Ltd.) was changed to 15 parts. Gelation occurred during the reaction.

  Using the aqueous emulsion adhesive compositions obtained in the above Examples and Comparative Examples, the following property measurements and physical property evaluations were performed. The results are shown in Table 1.

Property measurement (1) Non-volatile content It calculated by measuring the mass of a residue, after drying an aqueous emulsion adhesive composition at 105 degreeC for 1 hour.

(2) Viscosity The viscosity was measured at 10 rotations using a BH viscometer under the condition of 23 ° C.

(3) pH
Measured with a pH meter.

(4) Glass transition temperature The film of the aqueous emulsion adhesive composition was measured with a differential scanning calorimeter.

Preparation base material of test piece: Commercial product 2.5 mm thickness MDF / olefin sheet (0.14 mm thickness)
Application amount: Wet 80g / m ²
Drying conditions: 80 ° C. × 15 seconds Clamping conditions: Room temperature × 1.0 kg / cm ² × 60 seconds Curing: 23 ° C. × 50% RH × 3 days Processing method: Aqueous emulsion type adhesive composition applied to olefin sheet Wet was applied at 80 g / m ² , dried at 80 ° C. for 15 seconds with a drier, then bonded to an MDF plate using a rubber roller, and cured for 3 days in an atmosphere of 23 ° C. and 50% RH.

Measurement of physical properties (1) Heat resistance creep resistance A test piece is cut to a width of 25 mm and left in an atmosphere at 60 ° C. for 10 minutes, and then a load of 500 g is applied to one end of the olefin sheet of the test piece and left for 1 hour. The peel length of the olefin sheet was measured after 1 hour.

(2) Normal peeling strength A test piece was cut to a width of 25 mm, and 180 ° peel strength was measured at a peel rate of 100 mm / min using Tensilon (manufactured by Orientec Co., Ltd.) in an atmosphere of 23 ° C. and 50% RH. did.

(3) Initial adhesive strength The adhesive is applied to the olefin sheet by an application amount of Wet 80 g / m ² , dried at 80 ° C. for 15 seconds with a dryer, and then bonded to the MDF plate using a rubber roller. Thereafter, the balance was immediately placed on an automatic balance, and the scale of the balance was measured when the sheet was pulled straight up.

(4) Gel fraction The aqueous emulsion adhesive composition was adjusted to a nonvolatile content of 20% by mass. Next, the adjusted aqueous resin composition was poured onto a glass plate on which a release film was pasted so as to be 3.6 g (solid content) per 120 cm ² . The aqueous emulsion type adhesive composition poured onto the glass plate was dried at 23 ° C. for 7 days to form a film. The obtained film was cut out to 20 mm × 20 mm, measured for mass, and then immersed in THF at 23 ° C. for 1 day. The immersed film was taken out, dried at 110 ° C. for 1 hour, measured for mass, and calculated by dividing the mass of the film after immersion by the mass of the film before immersion.

  From the results of Table 1, the water-based emulsion adhesive compositions of Examples 1 to 5 were superior to the water-based emulsion adhesive compositions of Comparative Examples 1 to 4 in superior heat resistance creep resistance, normal peeling strength, and initial adhesive strength. It can be seen that

Claims (6)

0.5 to 10 parts by mass of tackiness with respect to 100 parts by mass of (meth) acrylic acid alkyl ester (A) and other unsaturated monomer (C) containing vinyl acetate An aqueous emulsion adhesive composition for wrapping obtained by emulsion polymerization in the presence of an agent (D). The aqueous emulsion adhesive composition for lapping according to claim 1, wherein the glass transition temperature is -20 to -60 ° C. The aqueous emulsion type adhesive composition for wrapping according to claim 1 or 2, wherein the unsaturated monomer contains 3 to 15 parts by mass of the carboxyl group-containing unsaturated monomer (B). The aqueous emulsion type adhesive composition for wrapping according to claim 1, 2 or 3, wherein the unsaturated monomer contains 2 to 11 parts by mass of the other unsaturated monomer (C). The aqueous emulsion adhesive composition for lapping according to claim 1, 2, 3 or 4, wherein the tackifier (D) is a petroleum resin tackifier. The aqueous emulsion adhesive composition for lapping according to claim 1, 2, 3, 4, or 5 having a gel fraction of 55 to 85%.