JPH09235522A - Adhesive sheet for decoration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet for decoration using a vinyl chloride resin sheet as a base substrate, excellent in installing properties, also less in a change in adhering physical characteristics with time, and produced at a low cost. SOLUTION: This adhesive sheet for decoration obtained by providing an acrylic adhesive agent layer on one surface of a vinyl chloride resin sheet obtained by forming with a calendar formation of a mixture of a polyvinyl chloride and a plasticizer, consists of the plasticizer consisting of 55-96wt.% dioctyl phthalate, 4-45wt.% plasticizer having a higher molecular weight than that of dioctyl phthalate, and the acrylic adhesive agent layer consisting of an acrylic copolymer consisting of 100 pts.wt. b-butyl acrylate component, 4-9wt.% (meth)acrylic acid component and 0.05-0.2 pts.wt. hydroxyalkyl (meth) acrylate component, having 700000-950000 weight averaged molecular weight and cross-linked to have 35-50wt.% gel fraction directly after the formation with a cross-linking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative pressure-sensitive adhesive sheet having a vinyl chloride resin sheet as a base material, which is excellent in workability and has little change in adhesive property over time.

[0002]

2. Description of the Related Art A decorative pressure-sensitive adhesive sheet having a calendar-molded vinyl chloride resin sheet as a base material and a pressure-sensitive adhesive layer provided thereon has excellent weather resistance and is flexible, so that it has good workability and can be used outdoors or indoors. Widely used in. As the required quality of this decorative pressure-sensitive adhesive sheet, it is required that the adhesive force of the pressure-sensitive adhesive does not easily change over time, and that the decorative pressure-sensitive adhesive sheet does not float up from the adherend after construction as the base material and that the workability is good. It

Conventionally, an acrylic pressure-sensitive adhesive has been selected as the pressure-sensitive adhesive used for the vinyl chloride resin sheet from the viewpoint of durability, etc., and in order to satisfy the pressure-sensitive adhesive property, monomer composition, polymerization degree,
This is achieved by controlling the molecular weight distribution. The change in adhesive strength over time is generally due to the transfer of the plasticizer in the vinyl chloride resin to the adhesive layer,
In order to prevent this, a method of interposing a substance having a barrier property against a plasticizer between the pressure-sensitive adhesive layer and the vinyl chloride resin sheet has been performed. Further, in a decorative pressure-sensitive adhesive sheet using a soft vinyl chloride resin sheet as a base material, a certain amount of a plasticizer is mixed in advance in the pressure-sensitive adhesive to suppress the change with time of the adhesive force. 18486
The pressure sensitive adhesive described in Japanese Patent Publication is disclosed.

[0004]

Epoxidized soybean oil or the like is used in a vinyl chloride resin sheet to be calendered to prevent heat burn during molding depending on the conditions in the molding process. It is known that this epoxidized soybean oil reacts with a carboxyl group in the pressure-sensitive adhesive over time to cause an increase in gel fraction, which causes a reduction in pressure-sensitive adhesive properties such as pressure-sensitive adhesive strength.

According to the method of interposing a substance having a barrier property against a plasticizer between the pressure-sensitive adhesive layer and the vinyl chloride resin sheet, the effect of suppressing the change in physical properties over time can be obtained, but the barrier layer is provided. This is disadvantageous because the number of steps is increased and the cost is increased. Furthermore, many substances having a barrier property are generally harder than vinyl chloride resin sheets, and there is a problem that the decorative pressure-sensitive adhesive sheet becomes too hard and the workability deteriorates.

Therefore, when the decorative pressure-sensitive adhesive sheet using the pressure-sensitive adhesive described in JP-A No. 2-18486 is used, the decrease in adhesive strength with time is suppressed, but due to the problems as described above, the curved surface is When it is installed on the floor, sufficient holding force required is not obtained.

The present invention solves the above-mentioned conventional problems and is excellent in workability using a vinyl chloride resin sheet as a base material, and
It is an object of the present invention to provide a decorative pressure-sensitive adhesive sheet which has little change in adhesive physical properties with time and can be manufactured at low cost.

[0008]

The decorative pressure-sensitive adhesive sheet of the present invention has an acrylic pressure-sensitive adhesive layer on one surface of a vinyl chloride resin sheet obtained by molding a mixture of a polyvinyl chloride resin and a plasticizer by a calendar molding method. It was provided,
The plasticizer comprises dioctyl phthalate in an amount of 55 to 96% by weight, and a plasticizer having a molecular weight higher than that of dioctyl phthalate in an amount of 4 to 45% by weight, and the acrylic pressure-sensitive adhesive layer comprises 100 parts by weight of an n-butyl acrylate component. ) An acrylic copolymer having a weight average molecular weight of 700,000 to 950,000 consisting of 4 to 9 parts by weight of an acrylic acid component and 0.05 to 0.2 parts by weight of a hydroxyalkyl (meth) acrylate component. It is characterized by being crosslinked so that the gel fraction immediately after molding is 35 to 50% by weight.

The vinyl chloride resin sheet is obtained by molding a mixture of polyvinyl chloride resin and a plasticizer by a calender molding method. The mixture of the above plasticizers is dioctyl phthalate (hereinafter abbreviated as “DOP”) 55-9.
It is characterized by comprising 6% by weight and 4-45% by weight of a plasticizer having a higher molecular weight than DOP.

The above-mentioned plasticizer having a higher molecular weight than DOP is intended to improve heat resistance and suppress migration to a pressure-sensitive adhesive. Specific examples include, for example, epoxidized soybean oil, Phthalic acid plasticizers such as diisononyl phthalate, octyldecyl phthalate and diisodecyl phthalate, adipic acid plasticizers such as diisononyl adipate and diisodecyl adipate, di-2-ethylhexyl azelaate, di-2-ethylhexyl sebacate. , Chlorinated paraffin, tri-2-ethylhexyl phosphate and the like. Of these, epoxidized soybean oil also has the function of a heat stabilizer and is suitable for calender molding.

If the DOP content is too small, a sufficient plasticizing effect cannot be obtained, and if the DOP content is too large, heat burning occurs during molding and the plasticizer easily migrates into the pressure-sensitive adhesive. % By weight, preferably 80-94
% By weight.

When the amount of the plasticizer added to the vinyl chloride resin is small, it is difficult to obtain a sufficient plasticizing effect, and when the amount of the plasticizer is large, the plasticizer is easily transferred to the pressure-sensitive adhesive. 2 to 23 parts by weight is preferable.

The vinyl chloride resin sheet used in the present invention may contain a heat stabilizer, a pigment, an ultraviolet absorber, a filler, etc., if necessary. Examples of the heat stabilizers include Ba / Zn stabilizers, Ba / Pb stabilizers, and Ca.
/ Zn-based stabilizer and the like. Also, as the pigment,
Examples thereof include carbon black, titanium white, quinacridone red and the like.

The acrylic adhesive used in the present invention is
100 parts by weight of n-butyl acrylate component, 4 to 9 parts by weight of (meth) acrylic acid component and 0.05 to 0.2 parts by weight of hydroxyalkyl (meth) acrylate component, and having a weight average molecular weight of 700,000 to 950,000. Consisting of an acrylic copolymer, the gel fraction immediately after molding is 35 to 35 due to the crosslinking agent.
It is characterized by being crosslinked to 50% by weight.

The acrylic adhesive used in the present invention is n
-By copolymerizing butyl acrylate as a main component, the adhesive property is less likely to deteriorate with time.

The (meth) acrylic acid component in the acrylic copolymer is copolymerized for the purpose of obtaining a sufficient adhesive force to an adherend having a high surface energy such as a metal plate. As described above, since it reacts with an epoxy-based plasticizer such as epoxy soybean oil contained in a vinyl chloride resin film that has been calendered to promote cross-linking and reduce the adhesive property over time, 100 parts by weight of n-butyl acrylate is added. On the other hand, it is 4 to 9 parts by weight. This is because if it is less than 4 parts by weight, sufficient adhesive force to a metal or the like cannot be obtained, and if it exceeds 9 parts by weight, the adhesive physical properties deteriorate with time.

The hydroxyalkyl (meth) acrylate component in the acrylic copolymer is copolymerized as a crosslinking base point, and examples thereof include hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. If the proportion of the hydroxyalkyl (meth) acrylate component is low, a sufficient degree of crosslinking cannot be obtained, and if it is high, the degree of crosslinking exceeds 50%. Therefore, 0.05 to 0 relative to 100 parts by weight of n-butyl acrylate. 0.2 parts by weight, preferably 0.1 to
0.15 parts by weight.

For the copolymerization of the above-mentioned respective monomer components, all polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization and bulk polymerization can be used, but copolymerization of (meth) acrylic acid or hydroxyalkyl (meth) acrylate is possible. Solution polymerization is preferred because sufficient polymerizability is obtained, the coating viscosity is easily controlled, and mixing with a crosslinking agent is easy.

When the weight average molecular weight of the acrylic copolymer is low, the degree of entanglement of the molecules is reduced, and when the gel fraction becomes the minimum value within the specified range, the holding force may not be exhibited. Further, if it is high, it becomes difficult to obtain a sufficient initial adhesive force, and therefore it is 700,000 to 950,000.

The acrylic pressure-sensitive adhesive used in the present invention may contain a tackifying resin, a plasticizer, an antioxidant, an ultraviolet absorber, a filler, etc., if necessary.

The above-mentioned acrylic pressure-sensitive adhesive is crosslinked by a crosslinking agent so that the gel fraction immediately after molding is 35 to 50% by weight.

Examples of the above-mentioned cross-linking agent include all that can react with a hydroxyl group derived from hydroxyalkyl (meth) acrylate. For example, tolylene diisocyanate (T
DI), naphthylene-1,5-diisocyanate, diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), trimethylolpropane modified TDI, and other isocyanate-based crosslinking agents are suitable. Are listed in.

If the amount of the above-mentioned cross-linking agent added is small, the gel fraction immediately after molding cannot be sufficiently obtained, so that the plasticizer is apt to migrate, and if it is increased, the cross-linking density becomes high and the flexibility is impaired, resulting in sufficient pressure sensitivity. Since it becomes difficult to obtain adhesiveness, the amount is 0.01 to 5 parts by weight, and preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the acrylic copolymer.

The present invention can achieve the object by selecting the composition of the pressure sensitive adhesive itself, its blending amount, the gel fraction immediately after molding, and the weight average molecular weight as described above.

(Function) The reason why the acrylic pressure-sensitive adhesive used in the present invention is unknown is that the copolymerization of n-butyl acrylate as a main component causes less deterioration of the pressure-sensitive adhesive property over time. There is. Furthermore, since the amount of the (meth) acrylic acid component is suppressed to 4 to 9 parts by weight with respect to 100 parts by weight of the n-butyl acrylate component, there is little progress of crosslinking even when a plasticizer having crosslinkability such as epoxidized soybean oil is transferred. The change in adhesive physical properties over time was suppressed.

Further, since the hydroxyalkyl (meth) acrylate component is also suppressed to 0.05 to 0.2 parts by weight, the gel fraction immediately after molding becomes 35 to 50%, and a slight increase in gel fraction is alleviated. The molecular weight is 7
By setting it to 0,000 to 950,000, it is possible to compensate for the decrease in the holding force due to the low gel fraction immediately after molding.

Further, the plasticizer used for the vinyl chloride resin sheet has a weight ratio of DOP to a plasticizer other than DOP of 9
Since it is a mixture of 6: 4 to 55:45, it is possible to minimize the deterioration of the adhesive property over time of the adhesive, and
By adding an epoxidized vegetable oil or the like, heat burning is less likely to occur during molding.

Since a step of interposing a substance having a barrier property against the plasticizer between the pressure-sensitive adhesive layer and the vinyl chloride resin sheet is not required, the manufacturing cost can be suppressed to that low.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the decorative pressure-sensitive adhesive sheet of the present invention will be described below. (Production of Vinyl Chloride Resin Sheet) According to the compounding composition shown in Table 1, vinyl chloride resin (Kanefuchi Chemical Co., Ltd., trade name "PSH"
10 ”), DOP (manufactured by Sekisui Chemical Co., Ltd.), epoxidized soybean oil (manufactured by Tokyo Fine Chemical Co., trade name“ NF-30 ”).
00)), adipic acid-based plasticizer (manufactured by Asahi Denka Co., Ltd., trade name “PN1430”), Ba / Zn stabilizer (manufactured by Sakai Chemical Co., trade name “LBZ-900”), carbon black (Dainichi Seika Co., Ltd.) Product, product name "Dymic Color"), and thoroughly kneaded by a calender method to give a thickness of 12
A vinyl chloride resin sheet of 0 μm was obtained.

[0030]

[Table 1]

(Preparation of Acrylic Pressure-Sensitive Adhesive and Preparation of Its Pressure-Sensitive Adhesive Layer) According to the composition shown in Table 2, each part of n-butyl acrylate, acrylic acid, and hydroxyethyl methacrylate were added together with 100 parts by weight of ethyl acetate in a separable flask. It was added to the mixture and heated to 70 ° C. Next, 0.1 part by weight of benzoyl peroxide was gradually added over 3 hours, and then the mixture was polymerized over 5 hours to obtain a solution of an acrylic copolymer. Furthermore, by adding 1.8 parts by weight of an isocyanate crosslinking agent (trade name "Coronate L-55E" manufactured by Nippon Polyurethane Industry Co., Ltd.) to 100 parts by weight of each of the above acrylic copolymers in terms of solid content, the acrylic type A solution of adhesive was obtained. Next, polyethylene was laminated on both sides, and a release paper whose release surface had been subjected to a release treatment was applied and dried to form an acrylic pressure-sensitive adhesive layer having a thickness of 40 μm.

[0032]

[Table 2]

(Examples 1 to 6 and Comparative Examples 1 to 5) According to the combinations shown in Table 3, a vinyl chloride resin sheet was laminated with an acrylic pressure-sensitive adhesive layer to obtain a decorative pressure-sensitive adhesive sheet.

Performance Evaluation With respect to the decorative pressure-sensitive adhesive sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 5, the pressure-sensitive adhesive force to the stainless steel plate (SP pressure-sensitive adhesive force),
The change with time of the gel fraction, the practical workability, and the presence or absence of heat burning on the surface were evaluated. Table 3 shows the results.

[0035]

[Table 3]

[Note] Practical workability evaluation method: diameter 100
125 mm on the concave side of the mm watch glass (made by Corning)
A sample with a size of 125 mm was curvedly formed so as not to contain air bubbles, and the sample was allowed to stand at 23 ° C. for 24 hours, and the floating state in the total area of the sample adhered was evaluated in five levels. 5: No rise 4: Number of rises within the maximum diameter of 10 mm is 2 or less 3: One-third of the total area is generated 2: Two-thirds of the total area is generated 1: Occurrence on the entire area

As can be seen from Table 3, all of Examples 1 to 5 have little change in adhesive strength and gel fraction with time, have good practical workability, and have no surface heat burn. It was On the other hand, in Comparative Examples 1, 2, and 5, since the gel fraction was remarkably increased, it was confirmed that the adhesive strength and the workability were deteriorated with time. Further, since the one of Comparative Example 3 has too low a molecular weight to obtain a sufficient holding force, floating occurs at the time of construction, and the one of Comparative Example 4 has too little plasticizer having a higher molecular weight than DOP and therefore is burned by heat. There has occurred.

[0038]

The decorative pressure-sensitive adhesive sheet of the present invention has the above-mentioned constitution, and the composition of the pressure-sensitive adhesive itself and its blending amount,
And, the gel fraction immediately after molding, by selecting the weight average molecular weight as described above, by using a calendar-molded vinyl chloride resin sheet as a substrate, excellent workability, and little change with time of adhesive properties Moreover, it is possible to produce an inexpensive decorative pressure-sensitive adhesive sheet.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09J 133/06 JDE C09J 133/06 JDE

Claims (1)

[Claims] 1. A decorative pressure-sensitive adhesive sheet having an acrylic pressure-sensitive adhesive layer provided on one surface of a vinyl chloride resin sheet obtained by molding a mixture of a polyvinyl chloride resin and a plasticizer by a calendar molding method, wherein the plasticizer is used. Is from 55 to 96% by weight of dioctyl phthalate and from 4 to 45% by weight of a plasticizer having a molecular weight higher than that of dioctyl phthalate, and the acrylic pressure-sensitive adhesive layer comprises 100 parts by weight of an n-butyl acrylate component and a (meth) acrylic acid component. 4-9 parts by weight and a hydroxyalkyl (meth) acrylate component 0.05-0.
2 parts by weight of an acrylic copolymer having a weight average molecular weight of 700,000 to 950,000 and having a gel fraction immediately after molding of 35 to 50% by weight, which is crosslinked with a crosslinking agent. Adhesive sheet for decoration.