JPH047379A - Primer composition and laminated structure using the same - Google Patents

Abstract

PURPOSE:To prevent migration of a plasticizer stably for a long period of time by using a primer which consists mainly of a copolymer of specific methyl methacrylate and an unsaturated organic compound having a carboxyl group. CONSTITUTION:A primer composition is obtained by compounding a copolymer having a weight-average molecular weight of 100,000 or above, which is obtained by copolymerizing 80wt.% or more methyl methacrylate and 0.5-20wt.% unsaturated organic compound having a carboxylic group (e.g. (meth)acrylic acid), with a tackifier and other additives, if required. Then the primer composition is applied onto the surface of a soft PVA resin molding to form a primer layer 1 to 20mu thick. A double-sided adhesive tape having acrylic adhesive layers is laminated on the primer layer, and an adherend is laminated by pressure on the tape to give a laminated structure.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for attaching a molded product made of a soft polyvinyl chloride resin containing a plasticizer to another adherend through an adhesive layer such as a double-sided adhesive tape. Primer composition suitable for use in pasting,
The present invention also relates to an adhesive structure using this primer composition.

(Prior Art) Soft polyvinyl chloride resins containing plasticizers are inexpensive, have excellent moldability and processability, and are widely used in daily necessities, industrial products such as pipes and hoses, transportation equipment, and all other fields.

The types of plasticizers usually include phthalate esters,
There are several types of plasticizers, such as phosphate esters and polymer plasticizers, but phthalate esters, especially dioctyl phthalate, are the most commonly used because they are inexpensive and have excellent plasticizing efficiency. .

However, when molded products containing them are used for a long period of time, these low-molecular plasticizers tend to bleed onto the surface, making the product sticky and stained. When the adhesive is attached to another object (hereinafter referred to as "adherent J"), there is a problem that the plasticizer migrates to the adhesive layer, reducing the adhesive strength and causing it to fall off from the adherend. This problem is especially strong when the molded product made of soft polyvinyl chloride resin is in the form of a sheet or plate, since the area to which the adhesive adheres is relatively large.

For example, in the case of a molding made of soft polyvinyl chloride resin that is attached to the car body, it is attached to the car body using double-sided adhesive tape, but when exposed to direct sunlight in midsummer, the molding itself can heat up to over 50°C. It is said to be warming. Since the rate at which plasticizer migrates into the adhesive of double-sided adhesive tape increases at an accelerating rate as the temperature rises, long-term durability tests for moldings are usually conducted at temperatures of 70°C or higher. Under such high temperatures, the plasticizer migration prevention function of (meth)acrylic acid ester resins, polyester resins, nitrile rubber resins, urethane resins, etc., which are commercially available as plasticizer migration inhibitors, does not work. , only a slight effect was observed for polymethyl methacrylate (PMMA).

Therefore, as a means to solve this problem, it has been proposed to interpose a primer layer between the molded article and the adhesive layer. (Japanese Unexamined Patent Publication No. 185675/1983, Japanese Patent Publication No. 1-42
(See Publication No. 987) (Problems to be Solved by the Invention) However, even the above-mentioned conventional techniques have not yet been able to completely prevent the plasticizer from migrating to the adhesive layer. The above conventional technology uses a primer mainly composed of acrylic polymer, and the aim is to utilize the acrylic polymer's ability to prevent plasticizer migration, but As the proportion increases, coating performance tends to decrease, and if the content is kept at a level that provides reasonable coating performance,
There is a relationship in which it does not have an effective plasticizer migration prevention function, and even if plasticizer migration is prevented initially, the migration gradually progresses during long-term use, making it impossible to achieve the initial purpose. It is.

After intensive research to solve the above-mentioned problems of the conventional technology, the present inventors focused on polymethyl methacrylate and studied its molecular weight dependence. It has been found that some of the following products stably exhibit the function of preventing plasticizer migration over a long period of time. However, depending on the application of the product, strong adhesive strength may be required not only under high temperature conditions but also at room temperature where the plasticizer does not migrate, and polymethyl methacrylate alone is not necessarily sufficient adhesive to satisfy such requirements. This problem was solved by creating a copolymer of methyl methacrylate and other monomers (as a result of intensive research, the present invention was completed).

(Means for solving the problems) 1 of the present invention has a weight average molecular weight of 100,000 or more,
The gist of the primer composition is a primer composition characterized in that the main component is a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group. A primer layer having a weight average molecular weight of 100,000 or more and containing a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group as a main component, and a molded product made of a flexible polyvinyl chloride resin, in this order. The gist of the sticking structure is that the sticking structure is laminated, and the third aspect of the present invention is the sticking structure according to claim 2, wherein the adhesive layer is a double-sided adhesive tape. This is the summary.

In the copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group used in the present invention, methyl methacrylate is preferably 80% by weight or more,
Below this range, the effect of suppressing plasticizer migration may not be obtained.

Examples of the unsaturated organic compound having a carboxyl group in the present invention include organic acids such as (meth)acrylic acid, (anhydrous) maleic acid, fumaric acid, and itaconic acid.

In addition to the above organic acids, 2-hydroxylethyl (meth)acrylate represented by the following general formula (1) and divalent carboxylic acids such as succinic acid, phthalic acid, and hexahydrophthalic acid may also be used. Compounds that are half esters with methyl methacrylate, etc. have particularly good compatibility with methyl methacrylate, so they are easier to copolymerize than with the above organic acids alone, such as itaconic acid. For example, compounds that are half esters with acrylic acid in the same proportion It was found that a stronger adhesive force could be obtained.

(However, R+ is a hydrogen group or a methyl group, and R2 is an ethyl group, a benzene ring, or a cyclohexane ring).
The amount is preferably 5 to 20% by weight, particularly preferably 3 to 1% by weight.
It is 0% by weight. In addition, if the mixing ratio of this unsaturated organic compound having a carboxyl group is 10% or less, other unsaturated organic compounds that do not contain functional groups having active hydrogen such as carboxyl groups or hydroxyl groups that can be copolymerized may be copolymerized. may be added to the monomer.

In the present invention, the reason why the adhesive strength with the adhesive layer is improved when methyl methacrylate is copolymerized with an unsaturated organic compound having a carboxyl group has not yet been completely elucidated, but the carboxyl group This is thought to be because it is connected to the polymer main chain by a long side chain, making it easy to move and exerting a strong interaction with the polar group in the adhesive.

Therefore, the copolymer consisting of methyl methacrylate and an unsaturated organic compound having a carboxyl group must have a weight average molecular weight of 100,000 or more, and if it is less than this, no improvement in adhesive strength can be expected. Also, the effect of suppressing plasticizer migration cannot be obtained.

There are no particular limitations on the method for producing the primer composition, and a polymerization catalyst such as azobisisobutyronitrile is mixed with a mixture of monomer methyl methacrylate and an unsaturated organic compound having a carboxyl group. In addition to bulk polymerization, known methods such as solution polymerization may be used for polymerization.

The upper limit of the weight average molecular weight of the copolymer is not particularly limited, but from the viewpoint of workability during polymerization and workability during primer application, a value of 500,000 or less is recommended for practical purposes. Ru.

It is optional to mix a tackifier resin and other additives into the copolymer composition of the present invention.

When applying the brimer composition of the present invention on the upper surface of the adhesive layer described below, there is no particular restriction on the thickness after drying, and from the viewpoint of preventing plasticizer migration, the thicker the better, but when applying From the viewpoint of workability and cost, 1-2
0μ is suitable.

As the adhesive forming the adhesive layer used in 2 or 3 of the present invention, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate and other known acrylic adhesives are preferred, and these are preferably crosslinked. More preferred. These adhesives also contain tackifying resins,
It is optional to use anti-aging agents and other additives.

As means for forming the adhesive layer used in 2 or 3 of the present invention, the adhesive may be directly applied to the adherend, or a soft polychlorinated resin may be formed with a primer layer made of the brimer composition of 1 of the present invention in advance. It may be coated on the primer layer of the vinyl resin molded product, but as in 3 of the present invention,
It is preferable to use double-sided adhesive tape because it requires less effort and forms a uniform layer.

When using double-sided adhesive tape, the base material may be polyethylene, ethylene-vinyl acetate copolymer, (meth)
Synthetic resin soft foam sheets made of acrylic acid ester copolymers, etc., chloroprene sheets, paper, nonwoven fabrics, acrylic rubber sheets, etc. are used. In particular, when synthetic resin soft foam sheets are used as materials, flexible polyvinyl chloride resin sheets are used. When the surface of a molded product or an adherend has a texture, it deforms to follow the uneven shape, so strong adhesive strength can be obtained. For example, a foam molded sheet of ethylene-vinyl acetate copolymer having fine open cells is sliced into an appropriate thickness and the skin layer is removed. In a foamed sheet from which the skin layer has not been removed, even if the foam itself is highly flexible, the skin layer has high rigidity and a large effective bonding area cannot be obtained. Note that when the foam is open-celled, the solvent will penetrate when applying the adhesive, so it is better to laminate a thin synthetic resin film in advance.

Further, as the adhesive forming the adhesive layer of the double-sided adhesive tape, the acrylic adhesive mentioned above is preferable.

As a method for obtaining the adhesive structure according to the second or third aspect of the present invention, as described above, the primer composition according to the first aspect of the present invention is applied to the surface of a molded product made of polyvinyl chloride resin to form a primer layer, Further, one adhesive side of a double-sided adhesive tape is pasted or an adhesive is applied thereon, and the adhesive side of the thus formed three-layer laminate is applied to the intended adherend. It is preferable to apply pressure by pressing the adhesive to obtain the most effective adhesion effect.

(Function) 1 of the present invention has a weight average molecular weight of 100,000 or more,
Since the primer composition is characterized by containing a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group as its main component, it can be applied to a soft polyester film using an adhesive such as double-sided adhesive tape. When a PVC resin molded product is pressure-adhered to an adherend, if it is interposed between the PVC molded product and the adhesive, the excellent plasticizer migration prevention function of the primer layer The primer layer prevents the plasticizer contained in the soft polyvinyl chloride resin molded article from migrating to the adhesive layer, and its effectiveness does not deteriorate, especially when exposed to high temperature conditions. or,
Due to the excellent adhesive force possessed by the primer layer, the adhesive force with the adhesive layer is also improved regardless of the temperature conditions.

In the second aspect of the present invention, the adherend, the adhesive layer, and the weight average molecular weight are 1.
00,000 or more, and a primer layer mainly composed of a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group, and a flexible polyvinyl chloride resin molded article are laminated in this order. Therefore, the excellent plasticizer migration prevention function of the primer layer interposed between the polyvinyl chloride resin molded product and the adhesive prevents the plasticizer contained in the soft polyvinyl chloride resin molded product from being removed. ,
The primer layer completely prevents the primer layer from transferring to the adhesive layer, and its effectiveness does not decrease, especially when exposed to high temperature conditions. Furthermore, the excellent adhesion function possessed by the primer layer improves the adhesion to the adhesive layer.

In the third aspect of the present invention, since the adhesive layer is formed of double-sided adhesive tape, the effort of applying the adhesive layer to the adherend is omitted, and the flexible polyvinyl chloride resin molded product provided with the primer layer is covered. It is easy to attach to the desired location on the body.

(Example) Examples of the present invention will be described below.

Su fan shell yu.

(2) Preparation of primer composition 95 parts by weight of methyl methacrylate monomer and 5 parts by weight of acrylic acid were blended, and 0.0% of azobisisobutylnitrile was added as a polymerization catalyst. Mix 5 parts by weight, 2
After bubbling nitrogen for 0 minutes, the mixture was reacted at a temperature of 60° C. for 24 hours, and further reacted at a temperature of 100° C. for 24 hours to complete the polymerization reaction.

Next, this reaction product was dissolved in methyl ethyl ketone to adjust the solid content concentration to 5% by weight.

■, Soft polyvinyl chloride resin sheet Made of polyvinyl chloride resin containing 30 parts by weight of DOP as a plasticizer, 30III+×
A rectangular sheet with dimensions of 8011I11 x 5IIm was produced.

■2-Ethylhexyl acrylate 89.5 as adhesive for production of double-sided tape
% by weight, 10% by weight of acrylic acid and 0.5% by weight of 2-hydroxyethyl methacrylate, and an adhesive component with a weight average molecular weight of 600,000 is crosslinked with an isocyanate compound (trade name: Coronate L) to create an adhesive. What was used as an agent,
The mixture was coated on a sheet-like carrier to obtain a pressure-sensitive adhesive sheet with a pressure-sensitive adhesive layer having a thickness of 60 μm. Next, this was transferred onto both sides of a tape base material made of a polyester film having a thickness of 38 μm which had been subjected to a corona discharge treatment in advance to obtain a double-sided adhesive tape.

(2) Preparation of test piece The primer composition was applied to one side of a flexible polyvinyl chloride resin sheet to a thickness of 1 μm after drying, and dried at room temperature for 15 minutes to form a brimer layer.

Next, apply 25+u+X 50+mX to the surface of the primer layer.
The above-mentioned double-sided adhesive tape in the form of a strip having a size of 158 μm was attached at room temperature (23° C.) to prepare a test piece.

Susashikan (.

A test piece was produced in the same manner as in Example 1, except that the methyl methacrylate monomer was 90 parts by weight and the methacrylic acid was 10 parts by weight.

A test piece was produced in the same manner as in Example 2, except that 0.2 parts by weight of 11 liters of azobisisobutylnitrile was used.

! Healing land.

As an unsaturated organic compound, 2-acryloyloxyethylsuccinic acid (manufactured by Yushi Kagaku Kogyo Co., Ltd., trade name: IOA-MS)
) A test piece was produced in the same manner as in Example 3, except that 10 parts by weight was used.

Urasenmasu i.

In addition, for the production of test pieces, a commercially available double-sided adhesive tape (manufactured by Tanemizu Kagaku Kogyo Co., Ltd., trade name: 516K) was used as a double-sided adhesive tape to be attached to the primer surface of the sheet coated with the primer used in Example 2. ) was applied to an acrylic-coated steel plate and the peeling force was measured.
The results obtained were equivalent to or better than the peeling force obtained in .

And comparatively ↓.

A test piece was produced in the same manner as in Example 1 except that azobisisobutyronitrile was used in an amount of 2.0 parts by weight.

Northern IL.

A test piece was produced in the same manner as in Example 1, except that 75 parts by weight of methyl methacrylate, 25 parts by weight of acrylic acid was used as the unsaturated organic compound, and dimethylformamide was used as the solvent.

This fl shadow.

A test piece was produced in the same manner as in Example 1, except that no primer was used.

Kitakami 11 Yu.

A test piece was produced in the same manner as in Example 1, except that aromatic isocyanate-based polyether polyurethane was used as the primer.

Le comparison l.

A test piece was produced in the same manner as in Example 1, except that vinyl chloride-vinyl acetate copolymer was used as the primer.

For each of the above Examples and Comparative Examples, the weight average molecular weight of the primer composition, the amount of plasticizer transfer, and the peeling force were measured. The results are shown in Table 1.

The above measurement methods are as follows.

■1 Weight average molecular weight A primer composition was prepared using tetrahydrofuran (THF) as a solvent so that the solid content concentration was 0.5% by weight, and subjected to gel permeation chromatography (GPC).
The weight average molecular weight in terms of polystyrene was measured by the method.

(2) Amount of plasticizer transfer After heat aging the test piece at 90°C, the double-sided adhesive sheet was peeled off, and the weight increase was measured to determine the amount of plasticizer transfer. Note that a release paper was attached to the opposite side of the double-sided adhesive sheet.

■ Peeling force (180° peeling force) When manufacturing a test piece, press a 25 mm wide double-sided adhesive sheet onto the surface of the primer by making one reciprocation with a 2 kg roller, and measure the normal peel force after 20 minutes. Separately, the sample was aged at 90°C for 72 hours, cooled to room temperature, and the aged peel strength was measured. The pulling speed at that time was 200+wm/min. However, in the case of Example 5, the measured peeling force was close to Oo.

Examples 6 to 9 and 6 to 9 In the production of test pieces, as a base material for double-sided adhesive tape,
The same procedure as described in "■1 double-sided adhesive tape" was used, except that a polyethylene foam sheet (manufactured by Tanezu Kagaku Kogyo Co., Ltd., trade name: Softlon IF) with a thickness of 1.2111111 and a foaming ratio of 20 times that had been previously treated with corona discharge was used. A double-sided adhesive tape of 10III1 width made of polyethylene foam is produced in the same manner as in "Manufacturing", and this is pasted onto the primer layer of a soft polyvinyl chloride resin sheet that has been coated with a primer composition to form a primer layer. The same procedures as those of Examples 1, 2, 3 and 4 and Comparative Example 1 were then applied to the adherend, which was a one-way press using a 5-g roller.
A pasted structure was prepared in the same manner as in 2 and 4.5.

For each of Examples 6 to 9 and Comparative Examples 6 to 9, the peel force was measured as follows. The results are shown in Table 1.

(2) Peeling force (0° peeling force) After each adhesive structure was left at room temperature for 24 hours, the peeling force was measured and taken as normal peeling force. Separately, the sample was aged at a temperature of 90° C. for 72 hours, cooled to room temperature, and allowed to stand for 3 hours or more for complete cooling, and then the peel force was measured and defined as the aged peel force. The pulling speed at that time was 20 (lu++/min).

Support 1 Adhesion 1 The base material of the double-sided adhesive tape was a 15 times foamed sheet made of ethylene-vinyl acetate copolymer (manufactured by Suisui Kagaku Kogyo Co., Ltd., trade name: Polara ES1501).
A pasted structure was prepared in the same manner as in Example 8, and the peel force was measured as described in (2) above. The results are shown in Table 1.

The base material of the double-sided adhesive tape is made of acrylic foam (U.S. 3
A bonded structure was prepared in the same manner as in Example 8, except that a sheet manufactured by Company M (trade name, VHB#4213) was used, and the peeling force was measured as in (2) above. The results are shown in Table 1.

Note)■, Peeling force (judgment): ◎: Extremely excellent aging peeling strength.

○: Excellent aging peeling force.

△: Poor aging peeling force.

×: The aging peeling force is significantly inferior.

(Blank below) (Effects) Since the primer composition according to the first aspect of the present invention has the same structure as the ridge, it can be interposed between the polyvinyl chloride resin molded product and the double-sided adhesive tape. For example, due to the excellent plasticizer migration prevention function possessed by the primer composition,
Plasticizer migration to the adhesive layer on the side of the double-sided adhesive tape that is in contact with the primer layer is completely prevented, and its effectiveness does not deteriorate even when exposed to high temperature conditions. The adhesive strength also improves the adhesive strength with the adhesive layer regardless of temperature conditions.

Since the adhesive structure according to the second aspect of the present invention has a structure similar to the ridges, the transfer of the preparation to the adhesive layer is completely prevented for the same reason as mentioned above, and regardless of the temperature conditions, The adhesive strength with the adhesive layer is also improved. Therefore, its range of applications is expanded.

In the third aspect of the present invention, since the adhesive layer is formed of double-sided adhesive tape, the effort of applying the adhesive layer to the adherend is omitted, and the flexible polyvinyl chloride resin molded product provided with the primer layer is coated with the adhesive layer. It is easy to attach to the desired location on the body. Therefore, the manufacturing process of the bonded structure is shortened, workability is improved, and products with stable quality can be obtained.This effect is achieved regardless of the size relationship between the adherend and the polyvinyl chloride resin molded product. remains unchanged. Therefore, its range of applications is expanded.

Claims (1)

[Scope of Claims] 1. A primer composition having a weight average molecular weight of 100,000 or more and comprising as a main component a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group. 2. Adherent, adhesive layer, primer layer having a weight average molecular weight of 100,000 or more and containing a copolymer of methyl methacrylate and an unsaturated organic compound having a carboxyl group as a main component, and soft polyvinyl chloride. An adhesive structure characterized by resin molded products being laminated in this order. 3. The adhesive structure according to claim 2, wherein the adhesive layer is a double-sided adhesive tape.