JP2011084625A - Adhesive composition and laminate body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition which has excellent adhesive performance even after being exposed to high temperature for a long time and can be used for usage for a laminate body of a solar cell back sheet or the like. <P>SOLUTION: A base material at least one of which is a polyester film, a polycarbonate film, an acrylic film or a fluorine resin film is laminated by using the adhesive composition containing a polycarbonate polyol, a tri- or more-functional isocyanate compound and an epoxy group-containing compound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to an improvement in heat resistance of a urethane resin adhesive composition, and an adhesive composition that can be used for applications that are exposed to a high temperature for a long time, such as a laminate for a solar battery backsheet. The present invention relates to a laminate using

  A solar cell is a power generation device that converts light energy into electric power, which can generate electricity continuously without the need for fuel, etc., has no moving parts, is easy to maintain, does not emit carbon dioxide and other greenhouse gases, roofs and walls It can be installed in a small area and has a feature that it does not take up space. It can be installed in other places such as outer space, mountainous areas, remote islands where power generation and feeding methods are difficult, and as a clean power generator in offices and homes. It has become so.

  With the widespread use of solar cells, research on solar cells has become more active, and not only cell parts such as power generation elements but also modules including peripheral members such as back sheets are actively researched. Therefore, the performance required for each member is further advanced. In addition, since a solar cell is installed in the place which receives an outdoor direct sunlight, one of the performance requested | required of a peripheral member is heat resistance.

Patent Document 1 discloses a solar cell back surface sealing sheet having a certain durability under an atmosphere of 105 ° C., and two or more layers of substrates are bonded with a urethane-based adhesive. However, as described above, the required heat resistance has been advanced and further improvement is required. Further, Patent Document 2 discloses a urethane-based pressure-sensitive adhesive that has little change over time in cohesive force and adhesive force even under high temperature or high temperature and high humidity, but it cannot meet the current required level.
JP 2008-4691 A JP-A-8-120249

  An object of the present invention is to provide an adhesive composition that has excellent adhesive performance even after being exposed to a high temperature for a long time and can be used for laminating a solar battery backsheet, and a laminate using the same. It is to be.

  The present invention is an adhesive composition characterized by containing a polycarbonate polyol, a trifunctional or higher functional isocyanate compound, and preferably further contains an epoxy compound. In addition, a laminate is characterized in that a base material, at least one of which is a polyester film, a polycarbonate film, an acrylic film, or a fluorine resin film, is laminated using the adhesive composition.

  The adhesive composition of the present invention has excellent adhesive performance even after being exposed to a high temperature for a long time. Therefore, it is suitable for uses requiring high heat resistance, particularly for laminating solar cell back sheets. Moreover, since the laminate of the present invention does not easily peel off even after being exposed to a high temperature for a long time, it is useful as a sealing structure for solar cells.

  The adhesive composition of the present invention uses polycarbonate polyol as the polyol. Polycarbonate polyol is carbonate compounds such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol , A compound obtained by reacting a diol compound such as triethylene glycol, tetraethylene glycol, 1,4-butanediol, 1,4-cyclohexanediol, 1,6-hexanediol, etc., which is chain-extended by an isocyanate compound. It may be good.

  In addition, within the range not impairing the object of the present invention, it is possible to use a polyol other than the polycarbonate polyol compound, for example, a polyester polyol in combination. However, when only the polyester polyol is used as the polyol, sufficient hydrolysis resistance is obtained. I can't get it. Therefore, the proportion of polyol other than polycarbonate in the polyol is preferably 20% by weight or less, more preferably 10% by weight or less, and even more preferably 5% by weight or less. Most preferably, only polycarbonate polyol is used as the polyol.

  Examples of the trifunctional or higher functional isocyanate compound used for the reaction with the polycarbonate polyol include triphenylmethane triisocyanate, 1-methylbenzole-2,4,6-triisocyanate, and dimethyltriphenylmethane tetraisocyanate. Further, isocyanurate bodies, biuret bodies, trimethylolpropane adduct bodies of various diisocyanate compounds may be used. The blending amount of the trifunctional or higher isocyanate compound is preferably used so that the NCO / OH ratio with the polycarbonate polyol is 1.0 to 10.0.

  By further adding an epoxy compound to the adhesive composition of the present invention, the heat resistance can be further improved. As the epoxy compound, various known epoxy resins such as bisphenol A type epoxy resin can be used. Moreover, the epoxy compound which has functional groups other than an epoxy group like an epoxy group containing silane coupling agent can also be used. The proportion of the epoxy compound is preferably 0.1 to 30% by weight, particularly preferably 0.1 to 10% by weight, based on the polyol.

  In addition to the above essential components, various materials can be blended in the adhesive composition of the present invention. Specifically, curing catalysts such as 1,8-diazabicyclo (5,4,0) undecene-7 (DBU) and its salts, tin-based catalysts, amine-based catalysts, calcium carbonate, cinnabar, kaolin, zeolite, bentonite , Crew, talc, graphite, asbestos, carbon fiber, silicic anhydride, magnesium carbonate, titanium oxide, shirasu balloon, glass balloon and other fillers, diluents, viscosity modifiers, antifoaming agents, anti-aging agents, dehydrating agents, etc. Is mentioned.

  Since the adhesive composition of the present invention has a high degree of heat resistance, it is suitable for applications where it is exposed to a high temperature for a long time. Moreover, since it has the outstanding adhesiveness with respect to the material used for the sealing part of a solar cell like a polyester film or a fluorine resin film, it is suitable for manufacture of the laminated body which laminated these.

  Hereinafter, based on an Example and a comparative example, this invention is demonstrated in detail. All blending ratios are based on weight. However, the present invention is not limited to the examples.

Example 1
100 parts by weight of a polyol having a structure of formula 1 (wherein R1 and R2 are each 50% of C5 or C6 linear alkyl randomly 50%) and a molecular weight of 2,000 and 7.7 of hexamethylene diisocyanate (HDI) Polycarbonate polyol 1 having a weight average molecular weight (Mw) of 20,000 was synthesized by extending the chain by reacting parts by weight. Example 1 A trimethylolpropane (TMP) adduct of hexamethylene diisocyanate (HDI) as a trifunctional or higher functional isocyanate compound was mixed with polycarbonate polyol 1 so that the NCO / OH ratio was 2.0. An adhesive composition was obtained. (Use ethyl acetate as the diluent solvent)

Example 2
An adhesive composition of Example 2 was obtained by further mixing 5 parts by weight of EP4100 (trade name, manufactured by Adeka ) as an epoxy compound with respect to 100 parts by weight of the adhesive composition of Example 1.

Example 3
By adding 5 parts by weight of SH6040 (trade name, manufactured by Toray Dow Corning Co., Ltd.) as an epoxy group-containing silane coupling agent to 100 parts by weight of the adhesive composition of Example 1, the adhesive of Example 3 was mixed. A composition was obtained.

Comparative Example 1
In Example 1, it replaced with the polyester polyol which consists of adipic acid, neopentyl glycol, and hexanezil instead of the polycarbonate polyol, and it carried out similarly to Example 1, and obtained the adhesive composition of the comparative example 1.

Comparative Example 2
In Example 1, instead of the trifunctional or higher functional isocyanate compound, HDI (manufactured by Nippon Polyurethane Industry), which is a bifunctional isocyanate compound, was mixed at a ratio of polyol to isocyanate (NCO / OH) of 2.0, It carried out similarly to Example 1 and obtained the adhesive composition of the comparative example 2.

Preparation method of test body Each adhesive composition of Examples and Comparative Examples was applied to a fluorine film so as to have a film thickness of 5 μm in solid content, and the solvent was volatilized. Crimping was performed using a laminator having a temperature of 90 ° C. A specimen was obtained by curing for 7 days in an atmosphere of 40 ° C.

Evaluation Method Normal strength was measured by cutting a test specimen into a width of 15 mm and peeling it off at a pulling speed of 50 mm / min. Further, the test specimen was left for 16 hours in a high pressure cooker (hydrolysis promoting device using pressurized steam: saturated type) under conditions of a pressure of 0.18 MPa and a temperature of 130 ° C. After accelerating the hydrolysis, the heat resistance was measured by similarly cutting to a width of 15 mm and peeling at a pulling speed of 50 mm / min.

  In each of the examples, the normal strength was excellent, and after the heat test, there was no significant decrease, and good strength was maintained. On the other hand, in each comparative example, the strength was greatly reduced after the heat test, and the heat resistance was insufficient.

Claims (4)

  An adhesive composition comprising a polycarbonate polyol, a trifunctional or higher functional isocyanate compound.   The adhesive composition according to claim 1, further comprising an epoxy compound.   The adhesive composition according to claim 1 or 2, wherein the trifunctional or higher functional isocyanate compound is an adduct of hexamethylene diisocyanate.   A base material in which at least one is a polyester film, a polycarbonate film, an acrylic film, or a fluorine resin film is laminated using the adhesive composition according to any one of claims 1 to 3. It is a laminate.