JPH0625330B2 - Adhesive composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive for polyethylene foam (hereinafter referred to as PEF) having excellent low-temperature adhesiveness.

[0002]

2. Description of the Related Art In recent years, as an energy saving measure, a construction method has been adopted for improving heat insulation performance of a roof, wall, etc. of a building in order to prevent heat from radiating from the building and block heat from the outside. As the heat insulating material, there are fiber type materials such as glass wool and rock wool, and foam type materials such as styrene foam, urethane foam and PEF. Especially, PEF does not absorb moisture or water because it has completely closed cells. Excellent in resistance, weather resistance and ozone resistance. Furthermore, since it is flexible, it can be used as a long product, and is attracting attention because it is suitable for construction on a large area such as a rooftop. Conventionally, as an adhesive applied to such a heat insulating material, a polychloroprene-based solvent type adhesive or the like is known, but it is necessary to apply the adhesive to both surfaces of the base and PEF, and the construction is complicated, and The deterioration of the working environment due to the organic solvent is not negligible, and there is a major drawback that the adhesiveness with PEF is lowered at low temperatures. Acrylic and synthetic rubber adhesives are also known as water-based adhesives. Acrylic water-based adhesives have excellent workability but low-temperature adhesiveness, and synthetic rubber-based adhesives have low temperatures. In addition to adhesiveness, it has a drawback in durability. Originally PEF has a very low polarity and hydrophobicity, making it difficult to bond,
Particularly for construction on site, there has been a demand for an adhesive that exhibits high adhesiveness in a wide range of environments from high temperatures in summer to low temperatures in winter.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive having high adhesiveness to PEF in a wide range of temperature environment from high temperature in summer to low temperature in winter.

[0004]

Means for Solving the Problems As a result of intensive investigations on the above-mentioned PEF adhesive, emulsion copolymerization of a vinyl ester (B) consisting of ethylene (A) and a vinyl ester of a tertiary carboxylic acid having an average carbon number of 10 is carried out. (Excluding the case where polyvinyl alcohol is used as a protective colloid.) An aqueous dispersion obtained by using a copolymer composition having an ethylene (A) content of 5 to 50% by weight and a vinyl ester (B) content of 50. The inventors have found an adhesive composition for PEF whose main component is an aqueous dispersion in which the glass transition temperature of the copolymer is -10 ° to -35 ° C at ˜95% by weight, and the present invention has been completed.

The PEF referred to herein is a polyolefin foam obtained by foaming a polyolefin represented by polyethylene by a physical or chemical method, and is not limited to polyethylene, so-called modified polyethylene obtained by copolymerizing a small amount of vinyl acetate or the like, and Polypropylene and the like are also included. The composition of the present invention can be applied to other plastic foams such as polystyrene and polyurethane, and various other adherend materials.

The ethylene (A) content of the vinyl ester (B) copolymer comprising ethylene (A) -tertiary carboxylic acid vinyl ester having an average carbon number of 10 which can be used in the present invention is 5 to 50% by weight. Is. If it is less than 5% by weight, the adhesiveness to polyethylene is lowered even if the glass transition temperature is -5 ° C or lower, and if it exceeds 50% by weight, the cohesive force is extremely lowered and the high temperature adhesiveness is lowered. Also vinyl ester (B)
The content is limited to 50 to 95% by weight. If it is less than 50% by weight, the cohesive force is lowered to lower the high temperature adhesive force, and if it exceeds 95% by weight, the low temperature adhesive force is lowered. As the vinyl ester, it is necessary to contain a vinyl ester of a tertiary carboxylic acid having an average carbon number of 10, but the vinyl ester of a tertiary carboxylic acid having an average carbon number of 10 in the vinyl ester (B). There is no particular limitation on the content rate of. The vinyl ester (B) may contain a vinyl ester such as vinyl acetate other than the vinyl ester of a tertiary carboxylic acid having an average carbon number of 10.

The third having an average carbon number of 10 used in the present invention
As the vinyl ester of a primary carboxylic acid (B), a tertiary vinyl carboxylate having an average carbon number of 10 (VeoVa 10,
Ciel Inc. product name) and the like.

Further, if the above-mentioned two components are within the specific ranges, it is possible to use together a component copolymerizable with them. Acrylic acid esters are particularly desirable, and butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate and the like are suitable. Other copolymerizable unsaturated compounds include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid and itaconic acid, methacrylic acid esters, N-vinylpyrrolidone, acrylamide, 2- Examples thereof include hydroxyethyl acrylate, N-methylol acrylamide, glycidyl methacrylate, vinyl chloride, diallyl phthalate, triallyl cyanurate, and ethylene glycol dimethacrylate.

The aqueous dispersion used in the present invention is obtained by pressure polymerization in the presence of a surfactant or a protective colloid (excluding polyvinyl alcohol). As the protective colloid (excluding polyvinyl alcohol), a maleic anhydride-isobutylene copolymer, a styrene-carboxylic acid modified copolymer, hydroxyethyl cellulose, hydroxypropyl cellulose or the like can be used. As the surfactant, generally commercially available anionic surfactant, nonionic surfactant, and cationic surfactant are used.

As the polymerization initiator, water-soluble inorganic peroxides or persulfates such as hydrogen peroxide and potassium sulfate, and azo compounds are used. Further, a redox-based initiator obtained by using these in combination with a reducing agent can also be used. As for the polymerization method, the vinyl ester may be added all at once, dividedly, or continuously.

The glass transition temperature of the aqueous copolymer dispersion used in the present invention is limited to -10 ° to -35 ° C. Although the value of the transition temperature varies depending on the measuring method, it means here the value by torsion braid analysis (TBA, frequency 1 Hz or less). Regarding TBA, for example, edited by The Chemical Society of Japan: New Experimental Chemistry Course, Volume 19, 904
Page (published by Maruzen in 1978). When the glass transition temperature is higher than -10 ° C, the room temperature and low temperature adhesive strength is lowered, and when the glass transition temperature is -35 ° C or lower, the high temperature adhesive strength is lowered, which is unsuitable.

A feature of the present invention is an adhesive that is applicable to PEF that is non-polar and in foam form. That is, most common water-based adhesives have a property that they can be a release agent as well as an adhesive property to PEF, and the well-known aqueous dispersions of ethylene-vinyl ester copolymers also have no adhesive property. Low. However, the glass transition temperature is -10 °
The emulsion copolymer containing ethylene (A) and a vinyl ester (B), which is a vinyl ester of a tertiary carboxylic acid having an average carbon number of 10 and having a vinyl ester (B) as the main component, is PE.
The adhesiveness to F is remarkably enhanced, and especially the low temperature adhesive strength is improved. Since the adhesive has ethylene as one of the main components, unlike a rubber-based adhesive, an oligomer is synthesized during polymerization, and a tackifying substance is automatically synthesized.
The adhesiveness to the foam or the adhesiveness to other substances is remarkably improved and the workability is improved.

If desired, the adhesive composition of the present invention may be mixed with an aqueous dispersion of another polymer, for example, a vinyl acetate polymer, an acrylic acid alkyl ester copolymer, an olefin polymer. Examples thereof include aqueous dispersions of polymers, vinyl chloride polymers, styrene-butadiene copolymers and the like. Further other commonly used additives for the adhesive of the present invention, such as thickeners, tackifiers, plasticizers, defoamers, pigments and isocyanate compounds, phenolic resins,
A melamine resin, a urea resin, a crosslinking agent such as an epoxy compound, etc. may be mixed, but as in the case of the other polymer aqueous dispersion mixture described above, the amount is not limited so that the performance of the composition is not deteriorated.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but these examples do not limit the present invention in any way. In addition, "part" and "%" in these examples mean a table on a weight basis unless otherwise specified.

The peel strength was measured by the following method. (1) Normal peel strength Peel angle 90 degrees, peel speed 200 mm / min, measurement temperature 2
It measured using the autograph on condition of 0 degreeC. (2) Low temperature peel strength The peel strength was determined by autographing at 5 ° C for 1 day. (3) High temperature peel strength The peel strength was determined by autographing at 50 ° C. for 1 day.

Example 1 In an autoclave equipped with a stirrer and a jacket, 5 parts of a nonionic activator (Nonipol 200) was dissolved in 70 parts of water, and ethylene (40 kg / cm ↑ 2) was added thereto. , Vinyl ester of tertiary carboxylic acid having an average carbon number of 10 (manufactured by VeoVa-10 Shell Chemical Co., Ltd.)
74 parts and vinyl acetate 4.5 parts with ammonium persulfate 2%
Continuous polymerization was performed using an aqueous solution. The stability of the obtained aqueous dispersion was good. The composition of the dispersion is shown in Table 1.
Table 2 shows the peel strength measured under the following conditions. Adhesion conditions: Slate plate (flat plate S of JIS-A5403, 6 m
200m (wet) / m ↑
2 After application, open time is 30 minutes, PEF (made by Toray) having a thickness of 20 mm, a width of 25 mm and a length of 100 mm is pressed once with a roller, and after curing at 20 ° C. for 1 day, the above (1) to
The adhesive strength measurement test of (3) was performed. As is clear from Table 2, the adhesiveness is good under the conditions of normal condition, low temperature and high temperature.

Example 2 Instead of 5 parts of the nonionic activator of Example 1, 1 part of hydroxyethyl cellulose and a nonionic activator (Nonipol 20) were used.
0) Polymerization was carried out under the same conditions as in Example 1 except that 4 parts were used. The composition of the obtained aqueous dispersion is shown in Table 1. The adhesive performance of the dispersion is shown in Table 2.

Comparative Examples 1 to 4 Polymerization was carried out by changing the monomer composition by the same polymerization method as in Examples.
The composition of the obtained aqueous dispersion is shown in Table 1. Table 2 shows the adhesive performance measured under the same conditions as in Example 1.

[0019]

[Table 1]

[Table 2]

[0020]

INDUSTRIAL APPLICABILITY The adhesive composition of the present invention has high PEF adhesiveness in a wide temperature range from low temperature to high temperature, and also has adhesiveness to various substances other than PEF. It is believed that the adhesive application is expanded by the adhesive according to the present invention. The adhesive composition of the present invention is a non-polluting aqueous emulsion, does not require a primer for an adherend, can be adhered by one-side application, has a large adhesive strength, cold resistance, heat resistance, Excellent aging resistance.

Claims (1)

[Claims] 1. An emulsion polymerization of a vinyl ester (B) comprising ethylene (A) and a vinyl ester of a tertiary carboxylic acid having an average carbon number of 10 (except when polyvinyl alcohol is used as a protective colloid). An aqueous dispersion having a copolymer composition of ethylene (A) content 5
˜50% by weight, vinyl ester (B) content 50˜95
% By weight, the glass transition temperature of the copolymer is −10 ° to −
An adhesive composition for polyethylene foam, which comprises an aqueous dispersion liquid at 35 ° C as a main component.