JPS6254836B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a protective material for aesthetic surfaces, and more specifically, it is suitable for protecting aesthetic surfaces on both sides or one side of acrylic plates, etc., and has a highly effective feel for use on base materials such as paper. A protective layer for aesthetic surfaces made of a pressure-adhesive composition is formed. That is, the protective layer has excellent releasability even after being attached for a long period of time, and is intended to protect aesthetic surfaces such as acrylic plates from being contaminated by the protective layer even after being peeled off. Next, in the drawings showing embodiments of the present invention, 1 is a base material made of paper, a synthetic resin film, or a sheet, and 2 is an aesthetic protective layer formed on one side of the base material 1. The pressure-sensitive adhesive composition made of the acrylic copolymer resin composition as the protective layer 2 for aesthetic surfaces is obtained by emulsion polymerization of three components (A), (B), and (C) in the following proportions. It is made by adding an appropriate amount of amines as a crosslinking agent to a water-dispersed emulsion. (A) Main component monomer (1) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 6 to 12 carbon atoms...20 to 90 (wt%) and (2) Containing 5 or less carbon atoms Acrylic acid or methacrylic acid alkyl ester having an alkyl group...20-80 (wt%) (B) Functional monomer (3) N-alkylolamide of acrylic acid or methacrylic acid (4) Glycidyl acrylate and glycidyl methacrylate (5) Allyl glycidyl ether [For the above (3), (4), and (5), use either alone or in an appropriate combination]
...1.0 to 20 (% by weight) (c) Functional monomer (6) α-olefin carboxylic acid
...2.0 to 15 (wt%) In addition, in practice, an anionic and nonionic mixed activator is used as an emulsifier for the monomer having the composition of components (A), (B), and (C) in the above blending ratio, Emulsion copolymerization is carried out using a persulfate or the like as a polymerization initiator and water as a dispersion medium. An appropriate amount of amines is added as a crosslinking agent to the polymer emulsion thus obtained. These amines include (a) aliphatic polyamines such as diethylenetriamine, triethylenetetramine, ethylenediamine, methylenediamine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperidine,
N,N'-bishydroxyethyl as polyether diamine, N-aminoethylpiperazine, m-xylene diamine or modified aliphatic polyamine;
Examples include N,N'-bishydroxypropylene diamine. (b) Aromatic amines such as m-phenylenediamine, diaminophenol, diaminodiphenylsulfone, benzidine, O-toluidine, 4,4'-thiodianiline, O-chloroaniline, 2,4-toluenediamine, diaminoditrisulfone , 4-chloro-O
-phenylenediamine, m-aminobenzylamine, etc. can be listed. (c) Secondary and tertiary amines For example, secondary amines include N-methylpiperazine, pyrrolidine, and morpholine, and tertiary amines include linear diamine, tetramethylguanidine, triethanolamine, N,N,N ′、
N'-tetramethyl-1,3-butanediamine,
Examples include N,N'-dimethylpiperazine, hexamethylenetetramine, pyridine, pyrazine, quinoline, benzyldimethylamine, and α-methylbenzylmethylamine. The most characteristic features of the adhesive composition according to the present invention produced as described above are: (a) crosslinking between carboxylic acid and alkylolamide; (b) crosslinking between alkylolamides; in this case, the remainder of the polymerization initiator Persulfates or catalysts such as NH ₄ C and P-toluenesulfones act to cause radical reactions and acidic condensation reactions, thereby significantly increasing the crosslinking rate. (c) Crosslinking between carboxylic acid and epoxy group In this case, an acidic catalyst such as P-toluenesulfonic acid acts as a catalyst to significantly increase the crosslinking rate. (d) Crosslinking between epoxy groups and the above-mentioned amines An emulsion of a highly elastic polymer composition obtained by a crosslinking reaction in combination of at least two of the above four types of crosslinking is used as a pressure-sensitive adhesive composition. Can be used as Further, basic monomers in the composition according to the present invention include hexyl acrylate as an acrylic acid or methacrylic acid alkyl ester having 6 to 12 carbon atoms;
These include n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate, or their methacrylates. Examples of monomers of acrylic acid or methacrylic acid alkyl esters having 5 or less carbon atoms include pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, and their methacrylates. The preferred usage ratio of acrylic acid alkyl esters or methacrylic acid alkyl esters is 70
~90% (wt%), and within that range, adjust the glass transition temperature at an appropriate point by combining a monomer with an alkyl group of 6 to 12 carbon atoms and a monomer with an alkyl group of 5 or less carbon atoms. . If a large amount of monomers having carbon number of 5 or less is used, the glass transition temperature becomes high, making it unsuitable for use in protective adhesive sheets. In addition, copolymerizable vinyl monomers, such as vinyl acetate, styrene, and acrylonitrile, which use a large amount of alkyl groups with 6 to 12 carbon atoms and can partially replace acrylic acid alkyl esters with 5 or less carbon atoms, are used. The amount that can be replaced by a polymer having a glass transition temperature of 30 DEG to 106 DEG C. is 5% by weight or less. Examples of crosslinking monomers include N-alkylolamides of acrylic acid or methacrylic acid, glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether. N-alkylolamides include N-methylol acrylamide,
These include N-ethyloacrylamide, N-propanol acrylamide, N-tertbutylacrylamide, diacetone acrylamide, and the like. Among these monomers, N-methylol acrylamide, glycidyl methacrylate, and glycidyl acrylate exhibit preferable effects. Monomers effective as α-olefin type carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, and the like. As effective amines that can be added to the emulsion as a crosslinking agent, ethylenediamine, triethylenetetramine, diethylenetriamine, etc. are suitable because they can be cured at room temperature. Examples of persulfates as polymerization initiators include potassium persulfate and ammonium persulfate. Examples of acidic catalysts that can be added to the emulsion include ammonium chloride, diammonium phosphate, P-toluenesulfonic acid, and amines. Examples include hydrochloride. As for the preferred manufacturing process for forming the protective layer 2 for aesthetic surfaces on the base material 1 such as paper, synthetic resin film, or sheet, the pressure-sensitive adhesive composition is applied to the base material 1 by a roll or other means, or as appropriate. The protective layer 2 for aesthetic surfaces may be formed by spraying by any means.
A release paper (not shown) is attached to the protective layer 2, and when it is attached to an aesthetic surface such as an acrylic board, the release paper is peeled off and the protective layer 2 is attached to the aesthetic surface. The protective material for aesthetic surfaces constructed according to the present invention has a protective layer for aesthetic surfaces made of the above-mentioned pressure-sensitive adhesive composition formed on the base material, so it can reliably protect aesthetic surfaces such as acrylic boards. I will be able to accomplish it. That is, when the protective material according to the present invention is applied to a decorative surface, it: ◎ Will not naturally peel off due to aging or changes in climate. ◎ Stable peel strength and easy peeling.
Reattachment is also possible. ◎ Does not contaminate the aesthetic surface of the acrylic board. Next, examples of the present invention will be described in detail below along with comparative examples. (Parts...parts by weight) Example 20 parts of 2-ethylhexyl acrylate, 14 parts of n-butyl acrylate, 1.0 parts of N-methylol acrylamide, 2 parts of glycidyl methacrylate,
2 parts of acrylic acid, 0.8 parts of NS-230, 0.2 parts of Niurex Paste H and 58 parts of water were placed in a reaction vessel equipped with a stirrer and a dropping funnel, and polyvinyl alcohol as an emulsifier and chloride as a polymerization initiator were added. An appropriate amount of ammonium was added, and emulsion copolymerization was carried out by stirring using water as a dispersion medium. While stirring the polymer emulsion thus obtained at room temperature, 1.0 part of ethylenediamine as a crosslinking agent was gradually added over about 1 hour to obtain a pressure-sensitive adhesive composition. Note that the MI (melt index) of this pressure-sensitive adhesive composition was 20. Comparative Example 20 parts of 2-ethylhexyl acrylate, 16 parts of n-butyl acrylate, 1.0 part of N-methylolacrylamide, 2 parts of glycidyl methacrylate,
Add 0.8 parts of NS-230, 0.2 parts of Niurex Paste H, and 58 parts of water to ethylenediamine in the same manner as in the example using the same emulsifier and polymerization initiator.
A polymer composition was prepared by adding 1.0 part with stirring. However, the α-olefin carboxylic acid component as a functional monomer is missing. The MI of the polymer composition obtained in the above comparative example was 40. The polymers obtained in the above examples and comparative examples were applied to kraft paper (20 to 100 g/m ² ) with a roll,
The releasability of each was investigated. * NS-230 and Niurex Paste H are manufactured by NOF. The physical property data for each are shown below. * Note ● Adhesive force measurement conditions Peeling force unit g/50mm width Peeling speed 300mm/min Peeling angle 180° peeling Humidity pressure test 40℃ x 80% RH x 0.2Kg/m ² Heat resistance pressure test 50℃ x 0.2Kg/ m ² Room temperature pressure test 20℃ x 65% RH x 0.2Kg/m ² Adherent is methyl methacrylate resin plate (plate thickness 2mm)

[Table] As is clear from the table, in the case of the example, a more stable peel strength was obtained than in the case of the comparative example, and it was easy to peel and did not contaminate the aesthetic surface of the methyl methacrylate resin board. becomes.

[Brief explanation of the drawing]

The figure is a sectional view illustrating an embodiment of the invention. 1... Base material, 2... Protective layer for aesthetic surfaces.

Claims (1)

[Claims] 1. A water-dispersed emulsion obtained by emulsion polymerizing three components (A), (B), and (C) in the following proportions on one side of a base material such as paper, synthetic resin film, or sheet. On the other hand, a protection layer for aesthetic surfaces is formed by forming a pressure-sensitive adhesive composition made of an acrylic copolymer resin composition to which an appropriate amount of amines are added as a crosslinking agent as a protective layer for aesthetic surfaces. Material. (A) Main component monomer (1) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 6 to 12 carbon atoms...20 to 90 (wt%) and (2) Containing 5 or less carbon atoms Acrylic acid or methacrylic acid alkyl ester having an alkyl group...20-80 (wt%) (B) Functional monomer (3) N-alkylolamide of acrylic acid or methacrylic acid (4) Glycidyl acrylate and glycidyl methacrylate (5) Allyl glycidyl ether [For the above (3), (4), and (5), use either alone or in an appropriate combination] ...1.0 to 20 (wt%) (c) Functional monomer (6) α-olefin carvone acid
…2.0-15 (weight%)