JPS6253345B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an acrylic board with a protected aesthetic surface, and more specifically, the aesthetic surface on both or one side of the acrylic board is a removable surface made of a pressure-sensitive adhesive composition that is highly effective in use. It is protected by a protective layer. That is, even after the surface protective layer has been adhered for a long period of time, it has excellent releasability, and even after being peeled off, the aesthetic surface of the acrylic board is protected from being contaminated by the protective layer. Regarding the structure according to this invention, the following (A) and (B) are applied to the aesthetic surface on both sides or one side of the acrylic plate.
(c) 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 to a water-dispersed emulsion formed by emulsion polymerization of three components is used as a removable protective layer. It is characterized by being formed. (A) Main component monomer (1) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 6 to 12 carbon atoms; and (2) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 5 or less carbon atoms. Acid alkyl ester (B) Functional monomer (3) N-alkylolamide of acrylic or methacrylic acid (4) Glycidyl acrylate and glycidyl methacrylate (5) Allyl glycidyl ether (c) Functional monomer (6) α-olefin carbon Acids (However, for (3), (4), and (5), use any one of them alone or in an appropriate combination) Next, in the drawings showing the embodiments of this invention, 1 is an acrylic board, 2 is an acrylic board for aesthetic surfaces. It is a removable surface protective layer, and Figure 1 shows the acrylic plate 1.
When the surface protective layers 2, 2 are formed on both sides of the second
The figure shows a case where a surface protective layer 2 is formed on one side of an acrylic plate 1. The pressure-sensitive adhesive composition as the removable surface protective layer 2 is prepared by adding an appropriate amount of amine as a crosslinking agent to a water-dispersed emulsion obtained by emulsion polymerization of the following three components (A), (B), and (c). This is an acrylic copolymer resin composition to which the following compounds are added. (A) Main component monomer (1) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 6 to 12 carbon atoms; and (2) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 5 or less carbon atoms. Acid alkyl ester (B) Functional monomer (3) N-alkylolamide of acrylic or methacrylic acid (4) Glycidyl acrylate and glycidyl methacrylate (5) Allyl glycidyl ether (c) Functional monomer (6) α-olefin carbon Acids (However, for (3), (4), and (5), use any of them alone or in an appropriate combination) In this invention, the above (1) to (1) as components (A), (B), and (C) are used.
The preferred weight ratio of (6) can be exemplified as follows. (A) (1)...20-90% (2)...20-80% (B) Any one or more of (3)(4)(5)...1.0-20% (C) ( 6)...2.0 to 15.0% (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) above, Emulsion copolymerization is carried out using persulfates 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. Examples of the amines include (a) aliphatic polyamines such as diethylene polyamine, triethylene tetramine, polymethylene diamine, tetraethylene pentamine, diethylaminopropylamine, N-aminoethylpiperidine, polyetherdiamine, N-aminoethylpiperazine,
N,N'-bishydroxyethyl as 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, and the like. (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,
Examples include N',N'-tetramethyl-1,3-butanediamine, 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 NH ₄ CI, P-toluenesulfonic acid, etc. act as a persulfate or a catalyst to cause a radical reaction and an acidic condensation reaction, 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, the glass transition temperature is adjusted 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. 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-terbutylacrylamide, 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. Effective monomers that can be added to the emulsion as a crosslinking agent include (a) amines, such as ethylenediamine, triethylenetetramine, diethylenetriamine, etc., are most used for room temperature curing. (b) Examples of persulfates and acidic catalysts include potassium persulfate, ammonium persulfate, ammonium chloride, diammonium phosphate, P-toluenesulfonic acid, and amine hydrochloride. In order to form a removable surface protective layer 2 on both sides or one side of the acrylic board 1 for aesthetic purposes, a preferred method is to apply a suitable temperature to the acrylic board 1, and apply a pressure-sensitive adhesive composition thereto. The surface protective layer 2 is formed by coating with a roll or other means, or by spraying with an appropriate means, and is dried. The acrylic board constructed according to the present invention has its aesthetic side protected by a removable surface protective layer made of the above-mentioned pressure-sensitive adhesive composition, and does not require a base material such as paper on the composition side. The following effects can be sufficiently achieved, and since the composition does not include a base material such as paper, it is possible to save labor and manufacture, and to provide a product that is easy to manufacture and inexpensive. That is, the effects are as follows: ◎Does not naturally peel off over time or due to changes in climate. ◎Stable peel strength and easy peeling. ◎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. Example 1 From 10 parts of 2-ethylhexyl acrylate, 25 parts of ethylene acrylate, 3 parts of glycidyl methacrylate, 2 parts of methacrylic acid, 0.5 part of N-methylolacrylamide, 1.0 part of NS-230, 0.2 part of Niurex Paste H and 60 parts of water. A polymer composition obtained by adding 1.0 part of ethylenediamine to the polymer obtained is coated on a methacrylic resin plate using a coater or the like. Example 2 10 parts of 2-ethylhexyl acrylate, 25 parts of methyl acrylate, 3 parts of glycidyl methacrylate
2 parts of methacrylic acid, 1.0 parts of NS-230, 0.5 parts of Nitsusan Sunpase, and 60 parts of water, and 2.0 parts of ethylenediamine was added to the resulting polymer composition on a methacrylic resin plate using a coating machine or the like. Apply. Comparative example Polyvinyl alcohol (20%) is applied to a methacrylic resin board using a coating machine. *NS-230 and Niurex Paste H are manufactured by Nippon Oil & Fats, and polyvinyl alcohol is polyvinyl alcohol GH-17 manufactured by Nippon Gosei. 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

[Table] As is clear from the table, in the case of Examples 1 and 2, 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 acrylic board. becomes.

[Brief explanation of the drawing]

The figures illustrate embodiments of the present invention, and FIG. 1 is a cross-sectional view of an acrylic plate with protective layers formed on both sides, and FIG. 2 is a cross-sectional view of an acrylic plate with a protective layer formed on one side. 1... Acrylic board, 2... Surface protective layer.

Claims (1)

[Scope of Claims] 1. A water-dispersed emulsion formed by emulsion polymerization of three components (A), (B), and (c) as shown below is applied to the aesthetic surface of an acrylic plate on both sides or one side, and cross-linked thereto. Acrylic with aesthetic protection, characterized in that it 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 an agent as a removable surface protective layer. Board. (A) Main component monomer (1) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 6 to 12 carbon atoms; and (2) Acrylic acid or methacrylic acid alkyl ester having an alkyl group containing 5 or less carbon atoms. Acid alkyl ester (B) Functional monomer (3) N-alkylolamide of acrylic or methacrylic acid (4) Glycidyl acrylate and glycidyl methacrylate (5) Allyl glycidyl ether (c) Functional monomer (6) α-olefin carbon Acids (However, for (3), (4), and (5), use either alone or in an appropriate combination)