JPH03265673A - Primer composition and article laminated using same - Google Patents

Abstract

PURPOSE:To prepare the title compsn. which is interposed between a molded, plasticized PVC article and a self-adhesive layer used for sticking the article to an adherend and which perfectly prevents a plasticizer contained in the article from migrating to the self-adhesive layer by using a specific polymethyl methacrylate as the main component. CONSTITUTION:A polymethyl methacrylate having a wt.-average mol.wt. of 300000 or higher is used as the main component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides a method for attaching a soft polyvinyl chloride citrus molded product containing a plasticizer to another adherend through an adhesive layer such as a screen adhesive tape. Primer composition suitable for use when adhering to
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 it is attached to another object (hereinafter referred to as the "adherent"), the plasticizer migrates to the adhesive layer, reducing the adhesive strength and causing it to fall off from the adherend. In particular, this problem was particularly strong when the soft polyvinyl chloride resin molded product was in the form of a sheet, plate, etc., since the area of adhesion with the adhesive became relatively large.

For example, in the case of a molding made of soft polyvinyl chloride resin that is attached to the body of a car, it is attached to the car body via adhesive screen 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 screen 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. , polymethyl methacrylate (
PMMA) only had a slight effect.

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. The present invention has been completed based on the discovery that the present invention stably exhibits the function of preventing plasticizer migration over a long period of time.

(Means for Solving the Problems) The gist of the present invention 1 is a primer composition characterized in that the main component is polymethyl methacrylate having a weight average molecular weight of 300,000 or more. The second aspect of the invention is that an adherend, an adhesive layer, a primer layer mainly composed of polymethyl methacrylate having a weight average molecular weight of 300,000 or more, and a molded product made of a soft polyvinyl chloride resin are laminated in this order. The gist of the present invention is a sticking structure characterized in that the adhesive layer is a screen adhesive tape. be.

In the primer containing polymethyl methacrylate as the main component used in the present invention, the present inventors have investigated that polymethyl methacrylate, which is the main component, has a migration suppressing effect when its weight average molecular weight is 100,000 or more. appears, especially 30
At temperatures above 10,000 yen, migration of the plasticizer was almost prevented even under conditions of 90"C, and no decrease in the adhesive strength of the screen adhesive tape was observed. Therefore, the polymethyl methacrylate used in the present invention The average molecular weight must be 300,000 or more.

The method for producing the primer composition is not particularly limited, and includes mixing a polymerization catalyst such as azobisisobutyronitrile with methyl methacrylate as a monomer;
In addition to bulk polymerization methods, known methods such as solution polymerization can be used.

The upper limit of the weight average molecular weight of polymethyl methacrylate 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. be done.

When applying the primer 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. Further, these pressure-sensitive adhesives may optionally contain tackifying resins, 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 applied directly to the adherend, or a soft polychloride layer may be formed in advance with a primer layer made of the primer composition of 1 of the present invention. Although it may be applied on the primer layer of the vinyl resin molded product, it is better to use a screen adhesive tape as in 3 of the present invention because it is less troublesome and a uniform layer is formed. preferable.

When using a screen 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 irregularities, it deforms to follow the irregularities, 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 screen 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, Furthermore, one adhesive side of the screen adhesive tape is pasted or an adhesive is applied thereon, and the adhesive side of the thus formed three-layered laminate is applied to the intended adherend. Pressure adhesion is preferred because the most effective adhesion effect can be obtained.

(Function) The first aspect of the present invention is a primer composition characterized in that the main component is polymethyl methacrylate having a weight average molecular weight of 300,000 or more. When adhering a polyvinyl chloride resin molded product to an adherend by pressure, the excellent plasticizer migration of the primer layer can be achieved by interposing it between the polyvinyl chloride resin molded product and the adhesive. Due to the prevention function, the primer layer completely prevents the plasticizer contained in the soft polyvinyl chloride resin molded product from migrating to the adhesive layer, and the primer layer will prevent the plasticizer from migrating, especially when exposed to high temperature conditions. The effect does not decrease.

2 of the present invention has an adherend, an adhesive layer, and a weight average molecular weight of 3.
Since the adhesive structure is characterized by having a primer whose main component is polymethyl methacrylate and a soft polyvinyl chloride resin molded product laminated in this order, it is necessary to use a plasticizer for the same reason as mentioned above. , plasticizer migration to the adhesive layer is completely prevented by the primer layer.

In the third aspect of the present invention, since the adhesive layer is formed of a screen 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. It is easy to attach to the desired location on the body.

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

Husband man Yu.

■ Preparation of primer composition For 100 parts by weight of methyl methacrylate monomer,
0.2 parts by weight of azobisisobutyronitrile was mixed as a polymerization catalyst, and after bubbling with nitrogen for 20 minutes, the reaction was carried out at a temperature of 60°C for 24 hours, and then at a temperature of 100''C for 2 hours.
The bulk polymerization reaction was completed after 4 hours of reaction.

Next, this reaction product was dissolved in methyl ethyl ketone to adjust the solid content concentration to 5% by weight. The weight average molecular weight of the obtained polymethyl methacrylate was 35. lXl
It was 0'.

■ Soft polyvinyl chloride resin sheet A polyvinyl chloride resin containing 30 parts by weight of DOP as a plasticizer is used as a material, and 3 (1 + m x 80
A rectangular sheet with dimensions of s+m x 5 - was produced.

■Manufacture of 1-screen adhesive tape 2-ethylhexyl acyl acyl (as adhesive) 89.
5% by weight of acrylic acid, 10% by weight of acrylic acid, and 0.5% by weight of 2-hydroxyethyl methacrylate.
A pressure-sensitive adhesive obtained by crosslinking with the product (trade name: Coronate L) was applied to a sheet-like carrier to obtain a pressure-sensitive adhesive sheet having a thickness of 60 μm. Next, this was pre-treated with corona discharge to a thickness of 3.
It was transferred onto the screen of a tape base material made of 8μ polyester film to obtain a screen adhesive tape.

(2) Preparation of test piece The primer composition was coated on 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 primer layer.

Next, on the surface of the primer layer, apply 25×50 cm.
The above-mentioned screen adhesive tape in the form of a strip measuring 60 μm was attached at room temperature (23° C.) to prepare a test piece.

1 piece.

A test piece was produced in the same manner as in Example 1 except that azobisisobutyronitrile was used in an amount of 0.1 part by weight.

1 Hoganuki 1. Also, when manufacturing the test piece, a commercially available screen adhesive tape (manufactured by Tanezu Kagaku Kogyo Co., Ltd., product name: Example 1
The results obtained were equivalent to or better than the peeling force obtained in .

1. Add azobisisobutyronitrile to the north. A test piece was produced in the same manner as in Example 1, except that ONN was used.

L School Cheongjuku.

A test piece was produced in the same manner as in Example 1, except that azobisisobutyronitrile was used in an amount of 0.5 parts by weight.

And you are brave.

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

A plate of clay.

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

且Mu且工.

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.

(2) Prepare a 0 weight average molecular weight primer composition using tetrahydrofuran (THF) as a solvent so that the solid content concentration is 5% by weight,
The weight average molecular weight in terms of polystyrene was measured by gel permin chromatography (GPC) method.

(2) Plasticizer Transfer Amount After the test piece was heat aged at 90°C, the screen adhesive sheet was peeled off, and the increase in N amount was measured and determined as the plasticizer transfer amount. Note that a release paper was attached to the opposite side of the screen adhesive sheet.

■ Peeling force (180" peeling force) When manufacturing the test piece, after pressing the screen adhesive sheet on the surface of the primer, further press it back and forth with a roller,
The normal peeling force was measured after 0 minutes, and the peeling force was separately measured at 90'C for 7
After aging for 2 hours, it was cooled to room temperature and the aging peel strength was measured. The pulling speed at that time was 200 m5/min.

However, in the case of Example 3, the measured peeling force was close to 0°.

4 and 5 and 6-9 In the production of test pieces, as a base material for screen adhesive tape,
A polyethylene foam sheet 1 (1+n width After manufacturing a screen adhesive tape and pasting it onto the primer layer of a soft polyvinyl chloride resin sheet on which a primer layer was formed by applying a primer composition, The above Examples 1 and 2 and Comparative Examples 2.4 and 5 except that one-way pressing was performed with a 5Kg roller.
A pasted structure was prepared in the same manner as above.

For each of Examples 4 and 5 and Comparative Examples 6 to 8, 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 the normal peeling force. Further, after aging for 72 hours at a temperature of 90° C., the sample was cooled to room temperature and left to stand for 3 hours or more to completely cool, and then the peel force was measured and defined as the aged peel force. The pulling speed at that time was 20 (1+m/min).

Except that the base material of the screen adhesive tape was a 15 times foamed sheet (manufactured by Tanezu Kagaku Kogyo Co., Ltd., trade name: Borara ES1501) made of ethylene-vinyl acetate copolymer.
A pasted structure was prepared in the same manner as in Example 5, and the peel force was measured as described in (2) above. The results are shown in Table 1.

The base material of the edge construction screen adhesive tape is acrylic foam (U.S. 3
A pasted structure was prepared in the same manner as in Example 5, 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) 1. Regarding Comparative Example 3, the measurement of the amount of plasticizer transferred was continued even after 72 hours had elapsed, and a saturated state was reached in 7 days, and the amount transferred at the time of saturation was 35.5% by weight. .

2. Peeling force (judgment): ◎: The aged peeling force is significantly superior to that of commercially available samples.

O: The aged peeling force is superior to commercially available examples.

△: Aged peeling force is almost the same as that of the commercially available example.

×: Aging peeling force is inferior to commercially available examples.

(Blank below) (Effect) The first aspect of the present invention is a primer composition characterized in that the main component is polymethyl methacrylate having a weight average molecular weight of 300,000 or more. When the polyvinyl chloride resin molded product is pressure-attached to the adherend, if it is interposed between the polyvinyl chloride resin molded product and the screen adhesive tape, the excellent plasticizer contained in the primer composition can be used. The migration prevention function completely prevents the plasticizer from migrating to the adhesive layer on the side of the screen adhesive tape that is in contact with the primer layer, and its effectiveness does not deteriorate, especially when exposed to high temperature conditions. Therefore, its range of applications is expanded.

In the second aspect of the present invention, a screen adhesive tape is attached to an adherend, and a polychlorinated film is applied to the upper surface of the screen adhesive tape via a primer whose main component is polymethyl methacrylate having a weight average molecular weight of 300,000 or more. Since vinyl resin molded products are pressure-attached, when the adherend is relatively large and the polyvinyl chloride resin molded product is relatively small, it is easy to apply pressure and has excellent workability. Long-lasting effect. Therefore, its range of applications is expanded.

The third aspect of the present invention is an adhesive structure in which an adherend, a screen adhesive tape, a primer whose main component is polymethyl methacrylate having a weight average molecular weight of 300,000 or more, and a polyvinyl chloride resin molded article are laminated in this order. Therefore, the excellent plasticizer migration prevention function possessed by the primer completely prevents plasticizer migration to the adhesive layer on the side of the screen adhesive tape that is in contact with the primer layer, especially when exposed to high temperature conditions. does not reduce its effectiveness. Moreover, this effect remains the same regardless of the size relationship between the adherend and the polyvinyl chloride resin molded article. Therefore, its range of applications is expanded.

Claims (1)

[Scope of Claims] 1. A primer composition characterized by containing polymethyl methacrylate as a main component having a weight average molecular weight of 300,000 or more. 2. An adherend, an adhesive layer, a primer layer mainly composed of polymethyl methacrylate having a weight average molecular weight of 300,000 or more, and a molded product made of soft polyvinyl chloride resin are laminated in this order. pasting structure. 3. The adhesive structure according to claim 2, wherein the adhesive layer is a screen adhesive tape.