JP2000328036A - Adhesive composition for fluorine-containing film- laminated steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for a fluorine-containing film- laminated steel plate which laminates fluorine-containing films at a low temperature of about from 160 to 180 deg.C and imparts an excellent low-temperature processibility at around 0 deg.C to a fluorine-containing film-laminated steel plate after laminating fluorine-containing films with this adhesive. SOLUTION: A base agent contains 100 pts.wt. polymer wherein the main chain is a copolymer containing methyl methacrylate and ethyl methacrylate in a weight ratio of from 60:40 to 80:20 and the side chain is urethane-modified, and from 1 to 5 pts.wt. epoxysilane compound. A hardener contains from 3 to 100 pts.wt. isocyanate compound against 100 pts.wt. polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition used for laminating a fluorine film for a steel sheet, and more particularly, to a low temperature of about 160 to 180.degree.
The present invention relates to an adhesive composition for a fluorine-film-laminated steel sheet, which can be laminated with a fluorine film and can improve the workability of a steel sheet laminated with the fluorine film at a low temperature (about 0 ° C.).

[0002]

2. Description of the Related Art Conventionally, a thermosetting acrylic resin-based adhesive has been used as an adhesive for laminating a polyvinyl fluoride film (hereinafter referred to as a fluorine film) and a galvanized steel sheet. Examples of such an adhesive include JP-B-38-18530 and JP-B-38-2676.
No. 3 and Japanese Patent Publication No. 42-11918. However, these adhesives have a problem in that the laminating temperature at the time of lamination and bonding is as high as 200 to 240 ° C., and it is not possible to laminate a low-melting fluorine film having a design and embossed on the surface. . On the other hand, an acrylic resin-based adhesive containing a fluororesin and an epoxy resin has been proposed in, for example, Japanese Patent Application Laid-Open No. Hei 5-186775 for laminating a fluorine film having a design. However, these adhesives have a problem in that the workability of the laminated steel sheet, particularly the bending at a low temperature of around 0 ° C., is inferior.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to
An adhesive for a fluorine film-laminated steel sheet that can laminate and bond (lamination) a fluorine film at a low temperature of about 0 to 180 ° C., wherein the fluorine film-laminated steel sheet after laminating the fluorine film with the adhesive is used. An object of the present invention is to provide an adhesive composition for a fluorine film-laminated steel sheet which is excellent in workability at a low temperature of around 0 ° C.

[0004]

That is, the present invention provides a copolymer wherein the main agent comprises methyl methacrylate and ethyl methacrylate in a main chain in a weight ratio of 60:40 to 80:20, Urethane-modified polymer 100 in side chain
Parts by weight and 1 to 5 parts by weight of an epoxysilane compound, wherein the curing agent is an isocyanate compound and the polymer 1
Provided is an adhesive composition for a fluorine-film-laminated steel sheet, containing 3 to 100 parts by weight based on 00 parts by weight.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The adhesive composition for a fluorine film-laminated steel sheet of the present invention (hereinafter, referred to as the composition of the present invention) is a two-part adhesive type adhesive composition, and as a main component, an acrylic resin is added to ethyl methacrylate (EA). The glass transition temperature (Tg) is lower than that of a general acrylic resin by using a urethane-modified polymer containing the polymer and epoxysilane together with the polymer, and the adhesiveness to the fluorine film at a low temperature of about 160 ° C. is improved. It is an elevated composition. Further, the isocyanate compound contained as a curing agent has excellent adhesiveness to metal, and the fluorine film-laminated steel sheet obtained by using the composition of the present invention as an adhesive has good workability at low temperatures.

The polymer contained in the main component of the composition of the present invention is a copolymer whose main chain contains methyl methacrylate (MMA) and ethyl methacrylate (EA), and whose side chain is urethane-modified. It is. MMA and E in the main chain
The composition ratio of A is 60:40 to 80:20 by weight, preferably 65:35 to 75:25. MM in this range
By introducing EA into A and copolymerizing MMA and EA, the obtained composition of the present invention has a low Tg,
Further, the adhesion to the fluorine film is improved. Methacrylic acid (MAA) may be contained in the main chain as long as the object of the present invention is not impaired.

This polymer is urethane-modified. Here, urethane-modified refers to MMA,
It means that -COOCH ₃ which is a side chain of EA is polycondensed with a polyol having an isocyanate group at a molecular terminal to form a urethane bond. As described above, when the obtained composition of the present invention is used as an adhesive for a fluorine film-laminated steel sheet, the workability at a low temperature of about 0 ° C. can be improved by the urethane-modified polymer. Specifically, even if the laminated steel sheet is bent in a low temperature environment around 0 ° C., such as in winter, the end face of the fluorine film does not peel off. The polyol having an isocyanate group at a molecular terminal is a reaction product of a polyol and an isocyanate compound. Examples of the polyol include polyether polyols such as polypropylene polyols and polyethylene polyols; condensates of the polyether polyols with polybasic carboxylic acids such as adipic acid, fumaric acid, and maleic acid, and the reaction of castor oil or castor oil with ethylene glycol. Polyester polyols such as lactone polymers obtained by ring-opening polymerization of hydroxycarboxylic acids and polyhydric alcohols such as products, and caprolactone with an appropriate polymerization initiator; acrylonitrile and styrene in addition to the polyether polyols or polyester polyols And polymer polyols such as those obtained by graft polymerization of an ethylenically unsaturated compound such as These polyols may be used alone or in combination of two or more.

As the isocyanate compound, paraphenylene diisocyanate, tolylene diisocyanate,
Examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, octadecyl diisocyanate, 4,4'-diphenylmethane diisocyanate, triphenylene methane triisocyanate, and modified products thereof. These isocyanate compounds may be used alone or in combination of two or more.

The polyol having an isocyanate group at the molecular terminal is prepared by mixing the polyol and the isocyanate compound with an NCO / OH ratio of 1.0 to 2.5, particularly 1.5 to 2.5.
It can be obtained by reacting to 2.0.

The proportion of urethane modification by a polyol having an isocyanate group at the molecular terminal of the polymer is preferably 1 to 20% by weight, more preferably 5 to 15% by weight based on 100 parts by weight of the polymer. When the polymer is urethane-modified in this range, the resulting composition of the present invention can have excellent workability at a low temperature of about 0 ° C.

As a method for producing the polymer contained in the composition of the present invention, a monomer of MMA and EA is blended in the above-mentioned ratio, a polymerization initiator such as azobisisobutyronitrile and benzoyl peroxide, and a polymerization initiator such as mercaptan. Put into a reactor together with a chain transfer agent and mix well
For example, a method in which polymerization is performed by heating at a temperature of 00 ° C. for 4 to 8 hours.

The molecular weight of the polymer contained in the composition of the present invention thus obtained is from 70,000 to 13,000.
0, which is larger than a general acrylic resin. By having such a large molecular weight, this polymer is excellent in mechanical properties such as bending strength and tensile strength, and is excellent in adhesion to a fluorine film. In addition, the polymer has a glass transition temperature (Tg) of Tg (about 100%) of a general acrylic resin because EA is introduced into MMA in a specific range and is modified by urethane.
30 ° C.). For this reason, in the obtained composition of the present invention, the temperature at which the fluorine film can be laminated and adhered to the steel sheet (lamination temperature) is 160 to 180.
It can be as low as ° C. Further, by introducing EA in a specific range, the adhesiveness of the obtained composition of the present invention to a fluorine film becomes high. Furthermore, since the polymer is urethane-modified, the resulting composition of the present invention has excellent adhesiveness to a metal plate such as a galvanized steel sheet, and a fluorine film-laminated steel sheet manufactured using the composition of the present invention. Does not peel off the end face even if a process such as bending is performed at a low temperature of about 0 ° C. Because of the urethane modification, the above-mentioned excellent adhesiveness is secured. In general, the closer the solubility parameter (SP value) between the adhesive and the adherend is, the better the adhesiveness of the adhesive to the adherend is. However, in the composition of the present invention, the SP of the polymer, which is the main component of the main agent, is used. Since the value is 8.9 to 9.2, which is close to the SP value of the fluorine film as the adherend, the adhesiveness between the obtained composition of the present invention and the fluorine film is high.

The main component of the composition of the present invention contains an epoxy silane together with the polymer. Here, the epoxy silane is a compound having an epoxy group at one molecular terminal and a hydrolyzable alkoxysilyl group at the other molecular terminal. By containing the above-mentioned specific polymer and epoxy silane in combination in the main agent, the obtained composition of the present invention has excellent adhesiveness to a fluorine film and excellent adhesiveness to a metal plate. . The main agent contains epoxy silane instead of mercapto silane or amino silane. The choice of epoxy silane is
This is because a reaction with the isocyanate compound contained in the curing agent hardly occurs. Examples of the epoxysilane contained in the main component of the composition of the present invention include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like. The content of the epoxysilane in the composition of the present invention is 1 to 5 parts by weight based on 100 parts by weight of the polymer in the main component. If the content is 1 part by weight or more, the resulting composition of the present invention has excellent adhesion to a fluorine film. Even if the content of the epoxy silane is more than 5 parts by weight, the properties of the composition of the present invention obtained, such as adhesiveness, are not inferior. However, since epoxy silane is expensive, if it is added more than 5 parts by weight, The production cost of the composition of the present invention is undesirably high.

The main ingredient of the composition of the present invention may contain a solvent in addition to the above essential compounds. That is, it is preferable that the polymer is mixed with a solvent for adjusting the viscosity. As the solvent, a solvent that does not react with an isocyanate compound as a curing agent described later is used. For example, toluene, ethyl acetate and the like can be mentioned. The content of the solvent is
The amount is preferably 100 to 300 parts by weight based on 100 parts by weight of the polymer.

[0015] In addition to the above compounds, the main components of the composition of the present invention may further include a rust preventive pigment, a filler, an antioxidant, an antioxidant, and an antistatic agent as long as the object of the present invention is not impaired. , A flame retardant, an adhesion-imparting agent, and the like.

The above-mentioned main ingredient can be adjusted by putting the above-mentioned compound and other additives into a reaction vessel and sufficiently stirring the mixture to make it uniform. The main agent thus obtained may be stored in a container until use.

The curing agent contained in the composition of the present invention contains an isocyanate compound as a main component. By containing the isocyanate compound as a main component of the curing agent, the obtained composition of the present invention has good adhesiveness to a galvanized steel sheet or the like. As the isocyanate compound,
Examples thereof include paraphenylene diisocyanate, tolylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, octadecyl diisocyanate, 4,4'-diphenylmethane diisocyanate, triphenylene methane triisocyanate, and modified products thereof. These isocyanate compounds are
Species may be used alone or in combination of two or more. As such an isocyanate compound, a commercially available product can be used. For example, Sumidur N7 manufactured by Sumitomo Bayern Co., Ltd.
5 and the like. The content of the isocyanate compound in the composition of the present invention is based on 100 parts by weight of the polymer.
It is 3 to 100 parts by weight, preferably 5 to 30 parts by weight. This is because if the content is within this range, the adhesiveness of the obtained composition of the present invention to a galvanized steel sheet or the like will be good.

The curing agent may contain, in addition to the isocyanate compound, a filler, an antioxidant, an antioxidant, an antistatic agent, a flame retardant, an adhesion-imparting agent, etc. within a range not to impair the object of the present invention. Is also good. A curing agent obtained in this way,
The mixing ratio of the main agent and the main agent is 10% by weight of the main agent and the curing agent.
It is preferable that the ratio be in the range of 0: 1 to 100: 10. This is because in this range, the adhesion to the fluorine film and the adhesion to the metal are both good.

The composition of the present invention can be produced by mixing the above-mentioned base agent and curing agent. Since the composition of the present invention is of a two-liquid mixture type, the main component and the curing agent may be mixed and used when the composition of the present invention is used.

The composition of the present invention thus obtained has a Tg lower than that of a general acrylic resin at 30 to 50 ° C.
Since the adhesiveness to the fluorine film is excellent even at a low temperature of 160 to 180 ° C., the laminating temperature of the fluorine film can be as low as about 160 ° C. For this reason, even the embossed fluorine film having a high design property can be laminated without impairing the embossing. In addition, since the composition of the present invention contains an isocyanate compound as a curing agent, the composition has excellent adhesion to steel sheets such as galvanized steel sheets. As described above, when a fluorine film is laminated on a galvanized steel sheet or the like using the composition of the present invention, a low-temperature treatment (160
(Approx. ° C.), it is possible to obtain a fluorine-film-laminated steel sheet having a stable adhesive strength. Further, even when the obtained fluorine film laminated steel sheet is bent at a low temperature of around 0 ° C., good workability is exhibited without peeling off the end face.

The composition of the present invention is an adhesive used for bonding a fluorine film to a steel sheet. The fluorine film used is not particularly limited. A highly designable fluorine film which has been embossed is preferably exemplified. Fluorine film subjected to such embossing, as described above, if the lamination temperature is high, the embossing is impaired and lamination cannot be performed, but with the composition of the present invention, lamination can be performed at low temperature, The design of the fluorine film is not impaired. As the steel sheet on which the fluorine film is laminated, a galvanized steel sheet is used. The galvanized steel sheet may be a hot-dip galvanized steel sheet or an electro-galvanized steel sheet, but a hot-dip galvanized steel sheet is more preferable since the amount of plating can be increased within the same time. Fluorine film-laminated steel sheet using the composition of the present invention, the composition of the present invention, roll coating, spray coating, etc., coated on steel sheet,
At a temperature of 160 to 180 ° C., a fluorine film is laminated,
It can be manufactured by bonding. The fluorine film laminated steel sheet obtained in this way has excellent weather resistance, the fluorine film is hard to peel off, and it is hard to get dirty, so it does not require long-term maintenance than painted steel sheet, and it can be used for the outer wall of buildings such as factories and high speed. It can be suitably used for soundproof walls such as roads.

[0022]

The present invention will be described more specifically with reference to the following examples. (Examples 1 to 3 and Comparative Examples 1 to 5) The main agent and the curing agent were adjusted according to the composition shown in Table 1, and the main agent and the curing agent were mixed to produce a composition. The unit of the compounding amount is [parts by weight]. For the obtained composition, the adhesion of the fluorine film by lamination at a low temperature of the fluorine film, and the low temperature workability of the steel sheet obtained by manufacturing a fluorine film laminated steel sheet using the obtained composition, the method shown below Was evaluated.

1) Adhesion The compositions obtained in Examples and Comparative Examples were spray-painted on galvanized steel sheets, and a fluorine film (Tedlar, manufactured by DuPont) was laminated and bonded at 160 ° C. 2 at ℃
After standing for a period of time, the adhesion was evaluated according to the method described in JIS K 6744. In the table, ○ indicates that the film had good adhesion without peeling or lifting, and x indicates that the film had peeled. 2) Appearance after lamination at 160 ° C. It was observed whether the fluorine film could be laminated at 160 ° C. In the table, ○ indicates that the film could be laminated and had good appearance without peeling or lifting, and × indicates that the film could not be laminated and peeled. 3) Low-temperature workability of laminated steel sheet A fluorine film-laminated steel sheet was manufactured by the same method as the method of manufacturing a steel sheet used in the above-described adhesion test, and the temperature was 0 ° C.
After being stored for 3 hours, the steel sheet was bent so as to sandwich a 5-mm-thick iron plate, and was subjected to bending by cutting the tip portion with a knife. In the table, ○ indicates that the end face was not peeled off by bending and the adhesiveness was high, and x indicates that the end face was peeled off by bending.

[0024]

[Table 1]

<Compounds in Table> Main agent MMA-EA copolymer: MMA: EA = 50: 50, urethane modification ratio 10% MMA-EA copolymer: MMA: EA = 60: 40, urethane modification ratio 10% MMA-EA copolymer: MMA: EA = 70: 30, urethane modification ratio 10% MMA-EA copolymer: MMA: EA = 80: 20, urethane modification ratio 10% MMA-EA copolymer: MMA: EA = 90: 10, urethane modification ratio 10% MMA-EA copolymer: MMA: EA = 70: 30, urethane modification ratio 0.5% MMA-EA copolymer: MMA: EA = 70: 30, urethane modification ratio 25% PMMA: Acrylic resin Epoxy silane: A-187, manufactured by Nippon Unicar Isocyanate compound: Sumidur N75, manufactured by Sumitomo Bayer Urethane Co.

[0026]

The adhesive composition for a fluorine film-laminated steel sheet of the present invention has a lower Tg than a conventional acrylic resin, and therefore has excellent adhesion (adhesion) to a fluorine film at 160 to 180 ° C. The laminating temperature of the fluorine film can be 160 ° C., which is lower than the conventional laminating temperature. Therefore, a fluorine film having a high design property, such as embossing, can be adhered to the adherend without impairing the embossing. In addition, the fluorine film-laminated steel sheet manufactured using the composition of the present invention has excellent workability even at a low temperature of around 0 ° C. without the end face being peeled off by bending. Therefore, the composition of the present invention is suitably used as an adhesive for laminating a fluorine film.

Claims (1)

[Claims] The main agent is a copolymer whose main chain contains methyl methacrylate and ethyl methacrylate in a weight ratio of 60:40 to 80:20, and 100% by weight of a side chain-modified urethane-modified polymer. Parts and epoxy silane compounds 1 to 5
And a curing agent containing 3 to 100 parts by weight of an isocyanate compound based on 100 parts by weight of the polymer.