JPH0229105B2 - SETSUCHAKUYOSOSEIBUTSUOYOBISETSUCHAKUHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an adhesive composition containing an ethylene-vinyl acetate copolymer as a main component and a method for bonding an inorganic material and an ethylene resin using the adhesive composition. Conventionally, ethylene resin has been used as a coating resin for inorganic materials such as metal materials. However, although ethylene resin has excellent weather resistance and chemical resistance, it has the disadvantage of extremely poor adhesion to inorganic materials because it is nonpolar and has high crystallinity. . Therefore, in order to improve the adhesion of ethylene resin to inorganic materials, there are methods of surface treating the ethylene resin film or sheet, methods of modifying the ethylene resin with an unsaturated carboxylic acid, or methods of adding an adhesion promoter to the ethylene resin. A method of adding it has been proposed. The first method is to introduce polar groups into the surface of the ethylene resin film or sheet by subjecting the ethylene resin film or sheet to surface treatment such as acid treatment, flame treatment, corona discharge treatment, or radiation treatment. This is a method for improving adhesion to inorganic materials (Japanese Patent Publication No. 11597/1983). but,
This method has the drawbacks of complicated operation and insufficient adhesion of the surface-treated ethylene resin film or sheet. The second method is a method in which ethylene resin is modified by graft polymerization or copolymerization with unsaturated carboxylic acid to improve its adhesion to inorganic materials (Japanese Patent Application Laid-Open No. 1986-1999). No. 63492). but,
This method has the disadvantage that the modified ethylene resin has poor saltwater resistance, and steel pipes coated with this resin cannot be used under conditions where they come into contact with seawater or the like. The third method is a method of improving adhesion to inorganic materials by using a mixture obtained by adding an adhesion promoter such as peroxide or vinyl silane to ethylene resin (especially (Opening No. 50-29658). However, this method also has the disadvantage that the adhesion of the mixture to the inorganic material is not sufficient. Therefore, the inventors completed this invention as a result of extensive research into a method for adhering an ethylene resin to an inorganic material that does not have the above-mentioned drawbacks, and an adhesive composition that can be used therein. That is, this invention uses 100 parts by weight of an ethylene-vinyl acetate copolymer, 0.02 to 10 parts by weight of a silane compound having a (meth)acryloyloxy group, 0.02 to 5 parts by weight of an organic peroxide, and 0.1 part by weight of calcium or barium oxide. The present invention relates to an adhesive composition prepared by uniformly mixing up to 30 parts by weight of the organic peroxide under temperature conditions such that the organic peroxide does not substantially decompose. The present invention also provides an inorganic material and an inorganic material characterized in that the above-mentioned adhesive composition is interposed between an inorganic material and an ethylene resin film or sheet, and the adhesive composition is heat-pressed until the organic peroxide is decomposed. It relates to a method of adhesion with ethylene resin. By using the adhesive composition of the present invention, it is possible to adhere an inorganic material and an ethylene resin with a high adhesive force that cannot be obtained with conventional adhesive compositions. According to the method of this invention, temperature can be increased to 160℃ with simple operation.
Even at a relatively low bonding temperature below, it is possible to bond an ethylene resin film or sheet to the surface of an inorganic material to obtain a coating layer with excellent salt water resistance, which is advantageous in terms of energy saving. In this invention, an ethylene-vinyl acetate copolymer is used as the main component of the adhesive composition. The ethylene-vinyl acetate copolymer has a vinyl acetate unit content (sometimes abbreviated as VA content) of 5 to 35% by weight, particularly 8 to 25% by weight,
MI (melt index) is 0.1 to 50g/10 minutes,
Particularly preferred is about 0.5 to 10 g/10 minutes.
Ethylene-vinyl acetate copolymer contains ethylene-
In addition to vinyl acetate copolymers, high-density, medium-density or low-density polyethylene, polypropylene, block or random copolymers of ethylene and propylene, copolymers of ethylene and butene-1, ethylene-propylene - One or more mixtures of diene terpolymer rubbers (EPDM) or copolymers mainly composed of ethylene or propylene and containing small amounts of acrylic acid esters and vinyl compounds such as vinyl chloride. The content may be less than 50% by weight, particularly 30% by weight or less. The silane compound having a (meth)acryloyloxy group used in this invention includes γ-
Examples include methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane, β-acryloyloxyethylenetrimethoxysilane, and β-acryloyloxyethylenetriethoxysilane.
In addition to silane compounds having a (meth)acryloyloxy group, silane compounds having a (meth)acryloyloxy group include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, etc. Approximately 50% by weight of vinyl silane compounds
It may be contained in a smaller amount, especially 30% by weight or less. The mixing ratio of the silane compound is
Per 100 parts by weight of ethylene-vinyl acetate copolymer
The amount is 0.02 to 10 parts by weight, preferably 0.1 to 5 parts by weight. If the mixing ratio of the silane compound is outside the above range, the adhesive strength of the adhesive composition will decrease, which is not preferable. The organic peroxide used in this invention has a half-life temperature of about 110 to 200°C, particularly 140 to 200°C.
180°C, such as dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, di-tert-butyl diperoxy phthalate, tert-butyl peroxylaurate, and tert-butyl peroxybenzoate. oxymale acid, cyclohexanone peroxide, tert-butyl cumyl peroxide, 1,1-bis(tert-butyl peroxy)-3,
Examples include 3,5-trimethylcyclohexane. These organic peroxides may be used alone or in combination of two or more. The mixing ratio of the organic peroxide is 0.02 to 5 parts by weight, preferably 0.1 to 3 parts by weight, per 100 parts by weight of the ethylene-vinyl acetate copolymer. If the mixing ratio of the organic peroxide is less than the above-mentioned lower limit, the adhesive composition will not exhibit adhesive strength, and if the mixing ratio of the organic peroxide is more than the above-mentioned upper limit, ethylene-acetic acid will not be present during melt mixing of the adhesive composition. This is not suitable because crosslinking of the vinyl copolymer progresses excessively, making it difficult to mold the adhesive composition, and furthermore, the adhesive composition no longer exhibits adhesive strength. In this invention, an oxide of calcium or barium, preferably an oxide of barium, is used in an amount of 0.1 to 30 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of the ethylene-vinyl acetate copolymer. The use of oxides of metals other than calcium or barium is not suitable because the adhesive strength of the adhesive composition is low. Furthermore, if the mixing ratio of calcium or barium oxide is less than the above-mentioned lower limit, the addition has almost no effect on adhesive strength, and if the mixing ratio of calcium or barium oxide is more than the above-mentioned upper limit, the adhesive composition will melt. This is not preferable because it is difficult to mix and also reduces the adhesive strength of the adhesive composition. In the adhesive composition of the present invention, the organic peroxide does not substantially decompose the ethylene-vinyl acetate copolymer, the silane compound having a (meth)acryloyl group, the organic peroxide, and the oxide of calcium or barium. Under temperature conditions, preferably at a temperature in the range above the melting point (or softening temperature) of the ethylene-vinyl acetate copolymer and below 150°C, using a roll, kneader, Brabender, Banbury mixer, etc., preferably 1 It can be obtained by uniformly mixing for ~30 minutes. Here, in order for the organic peroxide to "substantially not decompose",
It is preferable that about 20% by weight or more of the organic peroxide mixed in the ethylene-vinyl acetate copolymer is not decomposed. If more than about 20% by weight of the mixed organic peroxide is decomposed, it is not preferable because it is difficult to obtain an adhesive composition with high adhesive strength. The adhesive composition of the present invention contains known antioxidants, metal deterioration inhibitors, ultraviolet absorbers, flame retardants, processability improvers, reinforcing agents, and fillers in types and amounts that do not impede the effects of the present invention. , an antistatic agent, an adhesion improver, an antiblocking agent, and other additives may be contained as appropriate. The adhesive composition of the present invention can also be used as an adhesive for inorganic materials or as a coating agent for inorganic materials. In the method of this invention, the above-mentioned adhesive composition is interposed between an inorganic material and an ethylene resin film or sheet, and the inorganic material and ethylene resin are bonded together under heat and pressure until the organic peroxide is decomposed. are bonded together using an adhesive composition. Inorganic materials to be bonded by the method of this invention include metals such as aluminum, iron, stainless steel, copper, zinc, lead, and tin-lead alloys, metals treated with chromate treatment and various plating treatments, and molded materials such as glass and ceramics. can be mentioned. In the method of the present invention, as a film or sheet for surface coating of an inorganic material, high density polyethylene, medium density polyethylene, low density polyethylene, or an ethylene-vinyl acetate copolymer having a vinyl acetate unit content of 10% by weight or less is used. , ethylene-
An ethylene resin film or sheet such as propylene copolymer is used. In the method of the present invention, the above-mentioned adhesive composition may be interposed between the inorganic material and the ethylene resin film or sheet using a method known per se. A method in which the adhesive composition is interposed between the adhesive composition and the resin film or sheet is prepared in advance under temperature conditions that do not substantially decompose the organic peroxide, preferably at least the melting point (or softening temperature) of the ethylene-vinyl acetate copolymer. An example of this method is to preform the material into a pellet, film, or sheet at a temperature of 150° C. or lower, and then interpose this preform between an inorganic material and an ethylene resin film or sheet. In either method, it is preferable to uniformly apply the adhesive composition to the surface of the inorganic material or ethylene resin film or sheet in a range of 0.01 mg/cm ² to 0.2 g/cm ² . In addition, in the method of the present invention, the organic peroxide mixed with the ethylene-vinyl acetate copolymer is mixed with the ethylene-vinyl acetate copolymer at the temperature and time of all the steps of the mixing step, the adhesion step, or the preforming step. Preferably, more than about 0.5% by weight of the polymer does not decompose. The reason for this is that if more than about 0.5% by weight of the organic peroxide decomposes, crosslinking of the ethylene-vinyl acetate copolymer may proceed excessively, making handling and preforming difficult. This is because it is difficult to obtain one with good strength. In the method of the present invention, the adhesive composition as it is, or an inorganic material with a film or sheet of the adhesive composition interposed therebetween, and an ethylene resin film or sheet are combined using, for example, a heated press, a heated pressure roll, etc. Heat and press until the organic peroxide decomposes. At this time, it is preferable to completely decompose the organic peroxide. In order to decompose the ethylene-vinyl acetate copolymer, for example, the ethylene-vinyl acetate copolymer must be heated at a temperature higher than the melting point (or softening temperature) of the ethylene-vinyl acetate copolymer and approximately 40 to 50 degrees Celsius lower than the one-minute half-life temperature of the organic peroxide. What is necessary is to maintain the temperature below the decomposition temperature of the copolymer and ethylene resin for about 2 to 20 minutes. The inorganic material and the ethylene resin film or sheet can be bonded by simply heating and pressing, but it is preferable to press using a heated press, a heated pressure roll, or the like. Applying pressure not only increases the adhesive strength, but also its uniformity. Generally, a pressure of 0.1 to 200 Kg/cm ² is sufficient. When an inorganic material and an ethylene resin film or sheet are bonded together by the method of this invention, not only a coating layer with high adhesion strength and excellent salt water resistance is obtained, but also almost no odor is generated, so it is environmentally friendly during the bonding process. This is very convenient. Next, examples and comparative examples will be shown. In Examples and Comparative Examples, the adhesive strength and salt water resistance of the adhesive compositions were determined as follows. 1 Measurement of adhesive strength Use a spacer to evenly sandwich adhesive composition pellets between Teflon plates and heat at 150℃ for 1 hour.
After preheating for minutes, use a heat press machine to heat to 150℃ for 10 minutes.
After heating at Kg/cm ² for 3 minutes, let it cool to a thickness of approx.
150μ film, length 3
cm, width 2 cm and used for gluing. The surface of a rolled steel plate with a length of 15 cm, width of 3 cm, and thickness of 0.1 cm was cut out by mechanical cutting from a rolled steel plate that passed the regulations of JIS G3141, and the surface was cleaned with Triclean, and then dried and surface-treated. This surface-treated rolled steel plate was coated with the above-mentioned film, and after preheating at a predetermined temperature for 1 minute, a length of 15
A low-density polyethylene sheet with a width of 1 cm, a width of 0.2 cm, and a thickness of 0.2 cm is placed on top of the film and heated to the specified temperature.
A test piece was prepared by bonding a steel plate and a polyethylene sheet by applying a load of 100 g/cm ² for 3 minutes.
Using this test piece, the tensile speed was 50 mm/min,
The 180 degree peel strength was measured at room temperature (23°C). 2 Salt water resistance test A test piece obtained in the same manner as the test piece for adhesion measurement was immersed in 10 wt% saline solution at 60°C, and the time required for the steel plate and polyethylene sheet to separate (holding time) was measured. I asked for it. The longer the retention time, the better the salt water resistance. In the descriptions of Examples and Comparative Examples, parts indicate parts by weight. Further, the symbols in Examples and Comparative Examples mean the following silane compounds or organic peroxides. A; γ-methacryloyloxypropyltrimethoxysilane B; γ-glycidoxypropyltrimethoxysilane C; vinyltrimethoxysilane a; dicumyl peroxide (1 minute half-life temperature;
171°C) b; Tertiary butyl peroxybenzoate (1 minute half-life temperature; 170°C) c; Tertiary butyl peroxyisopropyl carbonate (1 minute half-life temperature; 158°C) d; 1,1-bis (tertiary butylperoxy)-3,
3,5-trimethylcyclohexane (1-minute half-life temperature: 148°C) Examples 1 to 3 100 parts of ethylene-vinyl acetate copolymer with the VA content and melt index shown in Table 1, γ
- 1.3 parts of methacryloyloxypropyltrimethoxysilane (A), 0.5 parts of dicumyl peroxide (a) and 2.5 parts of barium oxide are mixed using a Brabender at 120°C for 3 minutes to form a uniform adhesive composition. Obtained. Using this adhesive composition, a rolled steel plate and a polyethylene sheet were bonded together by the method described above to prepare a test piece. Table 1 shows the adhesive strength and salt water resistance test results of this test piece. Comparative Examples 1-2 Barium oxide was not added (Comparative Example 1)
Alternatively, when mixing ethylene-vinyl acetate copolymer, silane compound, organic peroxide and barium oxide, the kneading temperature was 180°C for 20 minutes to completely decompose the organic peroxide ( Comparative Example 2) Table 1 shows the results obtained in the same manner as in Example 1 except for the following.

[Table] Examples 4 to 6 Table 2 shows the results obtained in the same manner as in Example 1 except that an organic peroxide of the type shown in Table 2 was added in place of dicumyl peroxide.

[Table] Examples 7 to 8 Same as Example 1 except that the amount of barium oxide was changed from 2.5 parts to 12.5 parts (Example 7) or calcium oxide was added in place of barium oxide (Example 8). Table 3 shows the results obtained in the same manner. Comparative Examples 3-4 Table 3 shows the results obtained in the same manner as in Example 1 except that titanium oxide was added instead of barium oxide (Comparative Example 3) or magnesium oxide was added (Comparative Example 4). Shown below.

[Table] Comparative Examples 5 to 6 Results obtained in the same manner as in Example 1 except that silane compounds of the types shown in Table 4 were added in place of γ-methacryloyloxypropyltrimethoxysilane (A). It is shown in Table 4.

[Table] Comparative Example 7 A commercially available maleic anhydride-modified polyethylene film was placed over a surface-treated rolled steel plate of the same type as used in Example 1, and a load of 100 g/cm ² was applied at 150°C for 3 minutes. A test piece was created by bonding a steel plate and a modified polyethylene film. When this test piece was subjected to a salt water resistance test in the same manner as in Example 1, the retention time was 11 hours.

Claims (1)

[Claims] 1. 100 parts by weight of ethylene-vinyl acetate copolymer,
0.02 to 10 parts by weight of a silane compound having a (meth)acryloyloxy group, 0.02 to 5 parts by weight of an organic peroxide, and an oxide of calcium or barium
An adhesive composition prepared by uniformly mixing 0.1 to 30 parts by weight under temperature conditions such that the organic peroxide does not substantially decompose. 2 100 parts by weight of ethylene-vinyl acetate copolymer,
0.02 to 10 parts by weight of a silane compound having a (meth)acryloyloxy group, 0.02 to 5 parts by weight of an organic peroxide, and an oxide of calcium or barium
An adhesive composition prepared by uniformly mixing 0.1 to 30 parts by weight under temperature conditions that do not substantially decompose the organic peroxide is interposed between the inorganic material and the ethylene resin film or sheet. , a method of adhering an inorganic material and an ethylene resin, characterized by heat-pressing until the organic peroxide decomposes.