JPWO2012020750A1 - Resin composition, metal coating using the same, and adhesive - Google Patents

Abstract

In the present invention, (1) polyester, (2) polyolefin, (3) epoxy compound, and (4) tackifier are (1) / (2) / (3) / (4) = 100 by weight ratio. / 1 to 50/1 to 30/1 to 30 in which the polyester (1) is a polyether diol having a number average molecular weight of 500 to 4000 with respect to all glycol components. It is a polymerized resin composition that has excellent adhesion and durability characteristics and excellent molding characteristics, even without pre-molding such as primer coating on smooth surfaces of metals such as steel plates and aluminum. A resin composition is provided.

Description

  The present invention provides adhesion characteristics (good initial adhesion to the adherend and long-term durability without requiring pre-molding such as primer coating on a smooth surface of metal such as steel plate or aluminum. , Having a high temperature durability). This resin composition is a resin composition having excellent durability characteristics and molding characteristics.

In automobile parts, the metal part is coated with a resin to achieve noise reduction and vibration suppression and reduce noise. Home appliance parts are coated with a resin for the purpose of electrical insulation.
When a metal part is molded, a method capable of following the shape is required. For example, a method of inserting a metal part into an injection mold and injecting a molten resin is used. In home appliances and automobiles, high heat resistance is required, depending on the usage environment of the parts, and therefore high crystalline resins are used. However, in the case of a highly crystalline resin, it is necessary to consider the influence of adhesive degradation due to residual crystallization caused by rapid crystallization, thermal contraction immediately after that, and gradually enthalpy relaxation. In order to solve the problem of lowering adhesiveness, generally, metal parts are molded after pre-molding treatment such as primer application and corona discharge treatment (see Patent Document 1 and Patent Document 2). However, the application of the primer agent has many problems such as bubbles remaining when the solvent evaporates, the use of an organic solvent as the solvent makes the working environment worse, and the manufacturing cost increases due to an increase in the number of steps. In the corona discharge treatment, there is a problem that the cost is high due to capital investment and uniform treatment on the metal surface is difficult, and the surface treatment cannot be performed in a short time.

  As a molding resin that solves the above-mentioned problems, a hot melt type resin can be cited (see Patent Document 3 and Patent Document 4). In order to reduce the viscosity at the time of molding, the hot melt adhesive that only heats and melts the resin solves the problem in the working environment of the solvent-containing system and the epoxy resin system. Moreover, since it hardens | solidifies only by cooling after a mold and expresses performance, productivity also becomes high. In addition, since a thermoplastic resin is generally used, it is possible to easily recycle the member by heating and melting and removing the resin even after the end of the product life. However, while having high potential as a molding resin, it has not been a material that can sufficiently replace pre-molding treatments such as primer application so far. Because it was not proposed.

  In addition, a hot melt type having high adhesiveness using a crystalline resin has been proposed (see Patent Document 5), but since it is used for sealing electric and electronic parts, it has high adhesiveness in low-pressure molding. Resin design that expresses. When this hot melt type resin is developed into a large molded product, a high injection pressure is required, so that adhesion to the mold surface, which is also a metal member, is noticeable, and the mold releasability is extremely poor. is there. In addition, because of low pressure molding, the molecular weight of the resin is suppressed, reliability is poor under long-term high-temperature environments, and there is a problem that the operating environment temperature is limited, so automobiles and home appliances that require high heat resistance Deployment in applications was difficult.

JP-A-6-255024 JP 2001-239548 A JP 2002-309205 A JP-A-8-325539 JP 2010-250471 A

  The present invention has been made to solve the above problems. The object of the present invention is to achieve adhesion characteristics (good initial adhesion to the adherend and long-term adhesion) without performing pre-formation treatment such as primer coating on smooth surfaces of metals such as steel plates and aluminum. It is to provide a resin composition having excellent durability and high-temperature durability) and durability characteristics (having high-temperature durability of mechanical properties even under long-term high-temperature environments). Furthermore, the object of the present invention is to provide excellent molding characteristics (excellent mold release from the mold, good appearance of the obtained molded article (no peeling from the adherend)) in addition to the above characteristics. It is providing the made resin composition.

  In order to achieve the above object, the present inventors have intensively studied and have proposed the following invention. That is, the present invention is as follows.

[1] (1) Polyester, (2) Polyolefin, (3) Epoxy compound, and (4) Tackifier are (1) / (2) / (3) / (4) = 100 / 1 to 50/1 to 30/1 to 30 in a proportion of 5 to 50 mol% of a polyether diol having a number average molecular weight of 500 to 4000 with respect to all glycol components. A resin composition characterized by comprising:

[2] The resin composition according to [1], wherein the (1) polyester is a crystalline polyester having a melting point of 160 ° C. or higher and 230 ° C. or lower.

[3] The resin composition as described in [1] or [2], wherein the (2) polyolefin is polyethylene or an ethylene copolymer and has a specific gravity of 0.95 g / cm ³ or less.

[4] The resin composition according to any one of [1] to [3], wherein the (3) epoxy compound is a bisphenol type epoxy resin or a novolac type epoxy resin.

[5] The resin composition according to any one of [1] to [4], wherein (4) the tackifier is a rosin compound.

[6] The resin composition according to [5], wherein the acid value of the rosin compound is 2 to 300 (KOH mg / g).

[7] The weight ratio of (1) polyester, (2) polyolefin, (3) epoxy compound, and (4) tackifier is (1) / (2) / (3) / (4) = 100 / The resin composition according to any one of [1] to [6], which is 10 to 30/5 to 20/5 to 20.

[8] The resin composition according to any one of [1] to [7], wherein the surface hardness measured based on ASTM D2240 is 35D or more.

[9] The elongation retention ratio at the time of cutting after 100 ° C. and 1000 hours heat aging test is 50% or more, and the elongation retention ratio at the time of cutting after 80 ° C., humidity 95% and high temperature and high humidity for 500 hours is 50% or more. The resin composition according to any one of [1] to [8].

[10] The resin composition according to any one of [1] to [9], wherein the resin composition is used for metal coating to coat a metal by injection molding.

[11] A metal-coated body obtained by coating a metal with the resin composition according to any one of [1] to [9] by injection molding.

[12] An adhesive comprising the resin composition according to any one of [1] to [9].

  According to the present invention, adhesive properties (good initial adhesion by injection molding and long-term durability, even without pre-molding treatment such as primer application to a smooth surface of a metal such as a steel plate or aluminum, It is possible to provide a resin composition excellent in high temperature durability). This resin composition is also excellent in durability characteristics (having high-temperature durability of mechanical properties even in a long-term high-temperature environment). Furthermore, in addition to these characteristics, it is also possible to impart excellent molding characteristics (excellent mold release from the mold, good appearance of the resulting molded product (no peeling from the adherend)) Become. As a result, the polyester resin composition for molding metal parts covering complex shapes sufficiently satisfies various performances such as sound deadening, vibration damping, electrical insulation, work environment, productivity and durability. The material to be made can be provided.

[(1) Polyester]
(1) The polyester used in the present invention is a copolymerized polyester comprising a dicarboxylic acid component and a glycol component, and a polyether diol having a number average molecular weight of 500 or more and 4000 or less is copolymerized in an amount of 5 mol% or more and 50 mol% or less with respect to all glycol components. A copolyester.
(1) The dicarboxylic acid component used in the polyester is preferably terephthalic acid or naphthalenedicarboxylic acid, and at least one of these is preferably 40 mol% or more of the total dicarboxylic acid component from the viewpoint of economy and heat resistance. 70 mol% or more is more preferable, 80 mol% or more is more preferable, and 90 mol% or more is particularly preferable. Examples of other dicarboxylic acid components include isophthalic acid.
(1) As glycol components other than the polyether diol used for polyester, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1, Examples include aliphatic glycols such as 4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Among these, in order to impart heat resistance, either ethylene glycol or 1,4-butanediol is preferable.

Specific examples of the polyether diol include polytetramethylene glycol, polypropylene glycol, a copolymer of tetramethylene glycol and neopentyl glycol, a copolymer of tetramethylene glycol and propylene glycol, and the like. From the viewpoints of economy and adhesiveness, polytetramethylene glycol and poly (tetramethylene glycol / neopentyl glycol) (copolymer) are particularly preferable.
(1) The reason why the polyether diol is copolymerized with the polyester is to achieve easy fine dispersion and mixing with the (2) polyolefin component, which will be described later, with an ultra-low density.
If the number average molecular weight of the polyether diol is less than 500, it may be difficult to achieve easy fine dispersion / mixing with the polyolefin. On the other hand, when the number average molecular weight exceeds 4000, the compatibility with the polyester portion other than the polyether diol portion of (1) is lowered, and it may be difficult to copolymerize in a block form. The number average molecular weight of the polyether diol is preferably 700 or more and 3000 or less, and more preferably 800 or more and 2000 or less. Moreover, when it exceeds 50 mol%, there exists a possibility that the cohesion force of polyester parts other than the polyether diol part of (1) may fall, and a favorable adhesive characteristic may be lost. If it is less than 5 mol%, there is a concern that the effect of copolymerization cannot be obtained. It is preferable that polyether diol is 5 mol% or more and 40 mol% or less with respect to all the glycol components, 7 mol% or more and 30 mol% or less are more preferable, and 10 mol% or more and 30 mol% or less are more preferable.

  (1) The polyester used in the present invention is preferably a crystalline polyester having a melting point of 160 ° C. or higher and 230 ° C. or lower so that it can be distributed at room temperature. (1) The melting point of the polyester is more preferably 180 to 220 ° C. When the melting point is less than 160 ° C., it is difficult to satisfy heat resistance characteristics for automobiles and home appliances. When the melting point is higher than 230 ° C., the heat resistance temperature of (3) epoxy compound or (4) tackifier is exceeded at the time of melting / dispersing, which may cause deterioration of the resin composition.

  (1) The reduced viscosity of the polyester used in the present invention is preferably 0.50 dl / g or more and 2.50 dl / g or less when measured by the measurement method described later. If it is less than 0.50 dl / g, the durability as a resin is low, and if it exceeds 2.50 dl / g, the wettability to the adherend may become insufficient. (1) The reduced viscosity of the polyester is more preferably from 1.00 dl / g to 2.00 dl / g, and even more preferably from 1.50 dl / g to 1.90 dl / g. The acid value is preferably 200 eq / t or less. Since (3) the epoxy compound described later is contained in the resin composition, 50 eq / t or less is particularly preferable in order to avoid gelation during mixing.

(1) Polyester used in the present invention is obtained by copolymerizing a polyether diol having a density of 1.10 g / cm ³ or less in order to achieve easy fine dispersion and mixing with (2) polyolefin having an ultra-low density. Preferably it is.
Further, in addition to the polyether diol, a long-chain dicarboxylic acid component such as dimer acid or dimer diol and / or a glycol component may be included. For the purpose of imparting low-temperature adhesiveness, polyether diol may be used as a glycol component. It is particularly preferable to use it.

[(2) Polyolefin]
The polyolefin (2) used in the present invention is preferably an ultra-low density polyolefin having a specific gravity of 0.95 g / cm ³ or less. By using such an ultra-low density polyolefin, it is possible to easily finely disperse and mix with the originally incompatible polyester, and it is possible to obtain a good adhesive without requiring special kneading equipment. In addition, the low density and low crystallinity appropriately act on the temporal relaxation of the residual stress generated in the polyester during the injection molding.
Polyolefins having such properties are particularly preferred because polyethylene or ethylene copolymers are readily available, inexpensive, and do not adversely affect the adhesion to metals and films. Specifically, ultra-low density polyethylene, linear low density polyethylene, ethylene propylene elastomer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate-maleic anhydride terpolymer Polymer, ethylene-ethyl acrylate-maleic anhydride terpolymer, ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate terpolymer, ethylene-methyl acrylate-glycidyl methacrylate terpolymer An original copolymer may be mentioned. Among these, ultra-low density polyethylene and ethylene and other α-olefin copolymers are preferable.
A preferred range of the number average molecular weight of the polyolefin used in the present invention is 10,000 to 50,000.

Moreover, the compounding quantity of (2) polyolefin used for this invention is (1) / (2) = 100 / 1-50 by weight ratio with respect to (1) polyester. (2) When the amount of polyolefin is less than 1 part by weight, (1) Since it is difficult to relax strain energy due to crystallization of polyester or enthalpy relaxation, the adhesive strength tends to decrease with time. Moreover, when (2) polyolefin is mix | blended exceeding 50 weight part, there exists a tendency for the adhesive characteristic which a resin composition has to cancel. In addition, phase separation may adversely affect moldability such as a significant decrease in mechanical properties and delamination during injection molding.
In order to satisfy the initial adhesiveness as well as the long-term durability and high-temperature durability, and to satisfy the releasability and moldability (no peeling from the adherend), the weight ratio is (1) / ( 2) = 100/10 to 30 is preferable.

[(3) Epoxy compound]
The (3) epoxy compound used in the present invention is an epoxy resin having a glycidyl group in the molecule. The average number of glycidyl groups in the molecule is preferably 1.1 or more. Among these, a bisphenol type epoxy resin or a novolac type epoxy resin is preferable.
Specific examples include glycidyl ether types such as bisphenol A diglycidyl ether, bisphenol S diglycidyl ether, novolac glycidyl ether, and brominated bisphenol A diglycidyl ether. These epoxy compounds prevent (1) plasticization of the polyester, (1) limit the crystallization of the polyester, or suppress enthalpy relaxation, thereby preventing the occurrence of stress at the adhesive interface over time. In addition, the adhesion to the metal surface is improved. Therefore, in particular, in order to greatly improve the adhesive strength, (1) those having good compatibility with the polyester are preferable. Here, the number average molecular weight of the epoxy compound is preferably 450 to 40,000. If it is less than 450, the resin composition is very easy to soften and the mechanical properties are inferior, and if it exceeds 40000, the compatibility with (1) polyester becomes extremely poor, and the effect on adhesiveness may be impaired.

The compounding ratio of (1) polyester and (3) epoxy compound in the resin composition of the present invention is (1) / (3) = 100 / 1-30 in weight ratio. (3) When there are more epoxy compounds than 30 weight part, there exists a possibility that mechanical characteristics may be inferior and adhesiveness and heat resistance may fall. In addition, sufficient melting characteristics may not be obtained and moldability may be insufficient. On the other hand, if (3) the epoxy compound is less than 1 part by weight, the adhesion to the adherend may be inferior, and the adhesion may be reduced.
In order to satisfy the initial adhesiveness as well as the long-term durability and high-temperature durability, and to satisfy the releasability and moldability (no peeling from the adherend), the weight ratio is (1) / ( 3) = 100/5 to 20 is preferable.

The tackifier (4) used in the present invention preferably has a softening temperature of 60 ° C. or higher. If the softening temperature is less than 60 ° C., it takes time for cooling and solidification during injection molding, and the production cycle becomes longer, which is not preferable.
Specifically, rosin and rosin derivatives, terpene phenol, pure phenol resin, and the like can be used. More specific examples include (a) natural and modified rosins, such as gum rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin, (ii) natural and modified rosin. Glycerol glycerol and pentaerythritol esters, such as wood rosin glycerol ester, hydrogenated rosin glycerol ester, polymerized rosin glycerol ester, hydrogenated rosin pentaerythritol ester, and rosin phenol modified pentaerythritol ester ) Phenol-modified terpene resins and their hydrogenated derivatives, such as resin products obtained by condensation of bicyclic terpenes and phenol in acidic media, (e) thermoplastic alkylphenol resins. Mixtures of two or more of the tackifying resins as well as blends of the resin with a small amount (e.g., less than 10%) of a compatible resin may be used.

  In the present invention, the tackifier is preferably a rosin compound for the following reason. By using the rosin compound, the adhesive force is increased after the adhesion with the metal plate. This is because the rosin compound in the resin composition bleeds with respect to the metal bonding surface over time and the affinity with the metal surface increases, and the cohesive force as the rosin compound is improved.

  The acid value of the rosin compound is preferably 2 to 300 (KOH mg / g). This is because if it is less than 2 (KOH mg / g), delamination during molding due to insufficient compatibility with polyester, and if it exceeds 300 (KOH mg / g), there is a concern that the water resistance may be lowered. The acid value of the rosin compound is more preferably 200 to 280 (KOH mg / g).

The compounding ratio of (1) polyester and (4) tackifier in the resin composition of the present invention is (1) / (4) = 100 / 1-30 in weight ratio. (4) If the tackifier is more than 30 parts by weight, the mechanical properties of the resin composition are inferior and the adhesiveness and heat resistance may be reduced. In addition, problems such as delamination during injection molding due to phase separation may occur. On the other hand, when (4) the tackifier is less than 1 part by weight, the adhesion to the adherend is inferior, and the adhesiveness may decrease.
In order to satisfy the initial adhesiveness as well as the long-term durability and high-temperature durability, and to satisfy the releasability and moldability (no peeling from the adherend), the weight ratio is (1) / ( 4) = 100 / 5-20 is preferable.

As a method for determining the composition and composition ratio of the polyester-based resin composition used in the present invention, it is also possible to calculate from a proton integral ratio of ¹ H-NMR measured by dissolving a sample in a solvent such as deuterated chloroform. is there.

  The surface hardness of the resin composition of the present invention is preferably 35D or more when measured by the measurement method described later by adopting the above-described configuration. More preferably, it is 35D or more and 45D or less. If it is less than 35D, the amount of the polyether diol component increases, so that the crystallinity as a resin decreases, which is not preferable from the viewpoint of maintaining high-temperature durability. If it exceeds 45D, the amount of the dicarboxylic acid component is increased and the high-temperature durability tends to be improved, but there is a possibility that adhesion to a metal may be hindered by rapid crystallization and the accompanying thermal contraction.

  The resin composition of the present invention has an elongation retention ratio at break after cutting at 100 ° C. and 1000 hours of heat aging of 50% or more, and an elongation retention ratio at break after high temperature and high humidity treatment at 80 ° C., humidity 95% and 500 hours. % Or more is preferable. It is more preferable that the elongation retention during cutting after the heat aging test at 100 ° C. for 1000 hours is 75% or more, and the elongation retention during cutting after the high-temperature high-humidity treatment at 80 ° C. and humidity for 500 hours is 75% or more. .

  The (1) polyester production method of the present invention may be a known method. For example, the esterification reaction of the above dicarboxylic acid and diol component at 150 to 250 ° C., followed by 230 to 300 ° C. while reducing the pressure. The desired polyester can be obtained by polycondensation with. Alternatively, the target polyester is obtained by transcondensation at 230 ° C. to 300 ° C. under reduced pressure after a transesterification reaction at 150 ° C. to 250 ° C. using a derivative such as dimethyl ester of dicarboxylic acid and a diol component. Can do.

  Furthermore, when the resin composition of the present invention requires durability at a high temperature for a long time, it is preferable to add an antioxidant. For example, as a hindered phenol, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,1,3-tri (4-hydroxy-2-methyl- 5-t-butylphenyl) butane, 1,1-bis (3-t-butyl-6-methyl-4-hydroxyphenyl) butane, 3,5-bis (1,1-dimethylethyl) -4-hydroxy- Examples thereof include benzenepropanoic acid, pentaerythritol tetrakis (3,5-di-t-butyl-4-hydroxyphenyl) propionate, and the phosphorous-based 3,9-bis (p-nonylphenoxy) -2 , 4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa 3,9-di-phosphatonin spiro [5.5] undecane, tri (mono-nonylphenyl) phosphite, tri phenoxy phosphine include isodecyl phosphite. These can be used alone or in combination. The addition amount is preferably 0.1% or more and 5% or less based on the weight of the resin composition. If it is less than 0.1%, the effect of preventing thermal deterioration may be poor. If it exceeds 5%, the adhesion may be adversely affected.

Various other additives can be blended in the resin composition of the present invention. As additives, resins, inorganic fillers, stabilizers, UV absorbers, and anti-aging agents other than those of the present invention that are widely used as additives for thermoplastic adhesives are within the range that does not impair the characteristics of the present invention. Can be added.
The resin composition of the present invention preferably occupies 60% by weight or more in total of (1) polyester, (2) polyolefin, (3) epoxy compound, and (4) tackifier. The total of (1) to (4) is preferably 70% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more.

  Examples of the resin other than the present invention include polyester resins other than (1), polyolefin resins other than (2), thermoplastic resins such as styrene resins and polyurethane resins, phenol resins other than (4), phenoxy resins, petroleum resins and the like. Can be added.

  As the inorganic filler, talc, calcium carbonate, zinc oxide, titanium oxide, clay, bentonant, fumed silica, silica powder, mica and the like are blended by 40 parts by weight or less with respect to 100 parts by weight of the resin composition of the present invention. Can do.

  Other additives include crystal nucleating agents such as various metal salts, coloring pigments, inorganic and organic fillers, tackiness improvers, quenchers, metal deactivators, UV absorbers, HALS, and other stabilizers. An agent, a silane coupling agent, a flame retardant, etc. can also be added.

  As a method for producing the resin composition of the present invention, the polyester of the present invention, an epoxy compound, a polyolefin, and a rosin compound are usually used as a uniaxial or biaxial screw-type melt kneader or a kneader-type heater. Manufactured using a thermoplastic resin mixer and subsequently pelletized by a granulation process.

The resin composition of the present invention can be used for metal coating to coat a metal by injection molding. At this time, the resin composition can be directly coated by injection molding without requiring a pre-molding treatment such as primer application on a smooth metal surface. For example, by using pellets granulated by the above-described manufacturing method, inserting a metal plate as an adherend into the mold, and laminating a coating layer made of a resin composition on the metal plate by injection molding can get.
The resin composition of the present invention forms a coating layer on the metal as described above, and at the same time plays a role of an adhesive with the metal.

  As a method of using the resin composition of the present invention as an adhesive, preferably, pellets granulated by the above-described manufacturing method are used, a metal plate as an adherend is inserted inside the mold, and bonded by injection molding. It is a method to make it.

  Although the metal plate and the plastic plate are mainly bonded using the adhesive of the present invention, the metal can be used for a steel plate, aluminum or the like. Moreover, as a plastic film, it can use for polyester films, such as PET, a nylon film, a vinyl chloride film.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to the examples. In addition, each measured value described in the Example is measured by the following method.

Melting point:
Using a differential scanning calorimeter “DSC220” manufactured by Seiko Denshi Kogyo Co., Ltd., put 5 mg of measurement sample into an aluminum pan, seal it with a lid, and hold it at 250 ° C. for 5 minutes to completely melt the sample. Then, it was quenched with liquid nitrogen, and then measured from -150 ° C. to 250 ° C. at a rate of temperature increase of 20 ° C./min. The endothermic peak of the obtained curve was taken as the melting point.

Reduced viscosity:
0.10 g of sufficiently dried polyester resin was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6/4) and measured at 30 ° C. with an Ubellose viscometer.

Acid value:
A 0.2 g sample was precisely weighed, dissolved in 20 ml of chloroform, and titrated with 0.01 N potassium hydroxide (ethanol solution). Phenolphthalein was used as an indicator.

density:
Measured according to JIS K 7112.

Example of polyester production (Polyester A)
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser for distilling, 100 parts by weight of terephthalic acid, 82.4 parts by weight of 1,4-butanediol, and 0.4 parts by weight of tetrabutyl titanate were added. The esterification reaction was carried out at 2 ° C for 2 hours. After completion of the esterification reaction, 17.6 parts by weight of polytetramethylene glycol “PTMG1000” (Mitsubishi Chemical Corporation, density 0.98 g / cm ³ ) having a number average molecular weight of 1000 and hindered phenolic antioxidant “Irganox 1330” ”(Ciba Specialty Chemicals Co., Ltd.) was added at 0.8 parts by weight, and the temperature was raised to 255 ° C., while the system was slowly depressurized and subjected to a polycondensation reaction at 255 ° C. over 60 minutes. A polyester resin (A) was obtained. The melting point of this polyester resin (A) was 180 ° C., the glass transition temperature was −70 ° C., the reduced viscosity was 1.7 dl / g, and the acid value was 20 eq / t. Moreover, the ratio of the polytetramethylene glycol with respect to all the glycol components of a polyester resin (A) was 30 mol%.
(Polyester B)
100 parts by weight of terephthalic acid, 95.8 parts by weight of 1,4-butanediol and 0.4 parts by weight of tetrabutyl titanate were added, and an esterification reaction was performed at 200 to 250 ° C. for 2 hours. After completion of the esterification reaction, 4.2 parts by weight of polytetramethylene glycol “PTMG1000” (Mitsubishi Chemical Corporation, density 0.98 g / cm ³ ) having a number average molecular weight of 1000 and a hindered phenol-based antioxidant “Irganox 1330” ”(Ciba Specialty Chemicals Co., Ltd.) was charged with 0.8 part by weight, and the temperature was raised to 255 ° C., while the system was slowly depressurized and subjected to a polycondensation reaction at 255 ° C. over 60 minutes. Resin (B) was obtained. This polyester resin (B) had a melting point of 215 ° C., a glass transition temperature of −70 ° C., a reduced viscosity of 1.7 dl / g, and an acid value of 20 eq / t. Moreover, the ratio of the polytetramethylene glycol with respect to all the glycol components of a polyester resin (B) was 7 mol%.

Example 1
100 parts by weight of the polyester (A) obtained in the production example of the polyester, and 20 parts by weight of an ultra-low density polyethylene (Exelen EUL731 density 0.90 g / cm ³ manufactured by Sumitomo Chemical Co., Ltd.) as an polyolefin, 10 parts by weight of JER1007K (Japan Epoxy Chemical Co., Ltd., bisphenol type epoxy resin) and 10 parts by weight of KE604 (Arakawa Chemical Industries, Ltd. high acid value type rosin) as a tackifier at 200 ° C. Then, the mixture was kneaded and pelletized with a twin-screw extruder having three kneading zones. The following evaluation was performed using this pellet. The results are shown in Table 1.

Surface hardness:
Measured according to ASTM D2240.

SUS steel plate adhesion:
The pellets were molded using an injection molding machine. As the metal plate, a SUS steel plate having a width of 75 mm, a length of 150 mm, and a thickness of 1.0 mm was used. An electric injection molding machine EC-100N (manufactured by Toshiba Molding Machinery) was used as the injection molding machine, and the metal plate was inserted into a mold having a width of 75 mm, a length of 150 mm, and a thickness of 2.5 mm, and injection molding was performed. The molding temperature at this time was 170-210 ° C. from the bottom of the hopper to the nozzle tip, and the mold temperature was 40 ° C.
The adhesive strength was determined by performing a tensile test in an atmosphere of 25 ° C. using RTM100 manufactured by Toyo Baldwin and measuring the T-type peel strength at a tensile speed of 50 mm / min.
In the long-term adhesion durability test, the T-type peel strength of a sample prepared in the same manner was measured in a 25 ° C. atmosphere and a high temperature (80 ° C.) atmosphere for 1 day.
Further, the T-peel strength after a sample prepared in the same manner was allowed to stand for 1 month in a 25 ° C. atmosphere and a high temperature (80 ° C.) atmosphere was measured.
[Initial adhesion]
From the T-shaped peel strength, evaluation was performed according to the following criteria.
◎: 10 N / cm or more ○: 5 N / cm or more and less than 10 N / cm Δ: 1 N / cm or more and less than 5 N / cm ×: less than 1 N / cm or peeling immediately after injection molding [long-term adhesion durability]
Evaluation was performed according to the following criteria from the retention rate of the T-shaped peel strength.
◎: Holding strength of 90% or more ○: Holding strength of 50% or more and less than 90% △: Holding strength of adhesion of 25% or more and less than 50% ×: Less than 25% or occurrence of peeling

Release properties:
The releasability from the mold at the time of the injection molding was evaluated according to the following criteria.
◎: No sticking to the mold ○: There is a part of the sticking △: The entire molded product sticks to the mold but can be released ×: The molded product is completely stuck to the mold and the molded product breaks

Molded product appearance:
The molded article obtained by the injection molding was evaluated according to the following criteria.
◎: No delamination ○: Partial delamination is observed, but there is no problem as a product △: Partial delamination ×: Delamination

High temperature durability test:
<Creation of specimen>
The polyester elastomer pellets obtained by drying the measurement sample under reduced pressure at 100 ° C. for 8 hours were subjected to a cylinder temperature of 210 ° C., a mold temperature of 30 ° C., 100 mm × 100 mm × 2 mm using an injection molding machine (model-SAV manufactured by Yamashiro Seiki Co., Ltd.). Then, a dumbbell-shaped No. 3 test piece was punched from the flat plate.
<Evaluation of elongation retention during dry heat treatment and cutting>
After the dumbbell-shaped No. 3 test piece was treated at 100 ° C. for 1000 hours in a gear type hot air dryer (manufactured by Toyo Seiki Co., Ltd.), the elongation at break was measured according to JIS K 6251. For the test pieces not subjected to the dry heat treatment, the elongation at break was measured by the same method, and the retention rate of the elongation at break after the dry heat treatment was calculated.
<High temperature durability>
From the retention of elongation at break, evaluation was performed according to the following criteria.
◎: 75% or more ○: 50% or more and less than 75% △: 25% or more and less than 50% ×: Less than 25%

High temperature and high humidity test:
<Creation of specimen>
It was created in the same manner as described in the high temperature durability test measurement method.
<High temperature and high humidity treatment, method for evaluating elongation retention at cutting>
After the test piece was processed for 500 hours in a high-temperature and high-humidity tester (manufactured by Nagano Science Co., Ltd.) at 80 ° C. and 95% humidity, the elongation at break was measured in accordance with JIS K 6251. The test piece not treated under high temperature and high humidity was also measured for elongation at break by the same method, and the retention of elongation at break after high temperature and high humidity treatment was calculated.
<High temperature and high humidity durability>
From the retention of elongation at break, evaluation was performed according to the following criteria.
◎: 75% or more ○: 50% or more and less than 75% △: 25% or more and less than 50% ×: Less than 25%

Examples 2-16, Comparative Examples 1-6
Using the raw materials described in Tables 1 and 2, a resin composition was obtained in the same manner as in Example 1, and its performance was evaluated. The results are listed in Tables 1 and 2.

（＊１）エクセレン ＥＵＬ７３１（住友化学（株）社製、超低密度ポリエチレン；エチレンとαオレフィン共重合体、密度０．９０ｇ／ｃｍ^３）
（＊２）ハイゼックス２１００Ｊ（三井化学（株）社製、接着性ポリオレフィン；高密度ポリエチレン、密度０．９６ｇ／ｃｍ^３）
（＊３）ＪＥＲ１００７Ｋ（ジャパンエポキシレジン（株）社製、ビスフェノール型エポキシ樹脂、エポキシ価：２０００ｇ／ｅｑ）
（＊４）ＹＤＣＮ７０３（東都化成（株）社製、ノボラック型エポキシ樹脂、エポキシ価：２３０ｇ／ｅｑ）
（＊５）ＫＥ６０４（荒川化学工業（株）社製、高酸価型ロジン樹脂、酸価＝２４０ ＫＯＨ ｍｇ／ｇ、軟化温度＝１２５℃）
（＊６）ＫＥ１００（荒川化学工業（株）社製、エステルタイプロジン樹脂、酸価＝１ ＫＯＨ ｍｇ／ｇ、軟化温度＝１２５℃）
（＊７）Ｓ−１４５（ヤスハラケミカル（株）社製、テルペンフェノール樹脂、軟化温度＝１４５℃）
（＊８）Ｉｒｇａｎｏｘ１０１０（チバスペシャリティケミカルズ（株）社製、酸化防止剤）

(* 1) Excellen EUL731 (manufactured by Sumitomo Chemical Co., Ltd., ultra-low density polyethylene; ethylene and α-olefin copolymer, density 0.90 g / cm ³ )
(* 2) Hi-Zex 2100J (Mitsui Chemicals, Inc., adhesive polyolefin; high density polyethylene, density 0.96 g / cm ³ )
(* 3) JER1007K (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol type epoxy resin, epoxy value: 2000 g / eq)
(* 4) YDCN703 (manufactured by Toto Kasei Co., Ltd., novolac type epoxy resin, epoxy value: 230 g / eq)
(* 5) KE604 (manufactured by Arakawa Chemical Industries, Ltd., high acid value type rosin resin, acid value = 240 KOH mg / g, softening temperature = 125 ° C.)
(* 6) KE100 (Arakawa Chemical Industries, Ltd., ester type rosin resin, acid value = 1 KOH mg / g, softening temperature = 125 ° C.)
(* 7) S-145 (Yasuhara Chemical Co., Ltd., terpene phenol resin, softening temperature = 145 ° C)
(* 8) Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd., antioxidant)

（＊１）エクセレン ＥＵＬ７３１（住友化学（株）社製、超低密度ポリエチレン；エチレンとαオレフィン共重合体、密度０．９０ｇ／ｃｍ^３）
（＊２）ハイゼックス２１００Ｊ（三井化学（株）社製、接着性ポリオレフィン；高密度ポリエチレン、密度０．９６ｇ／ｃｍ^３）
（＊３）ＪＥＲ１００７Ｋ（ジャパンエポキシレジン（株）社製、ビスフェノール型エポキシ樹脂、エポキシ価：２０００ｇ／ｅｑ）
（＊４）ＹＤＣＮ７０３（東都化成（株）社製、ノボラック型エポキシ樹脂、エポキシ価：２３０ｇ／ｅｑ）
（＊５）ＫＥ６０４（荒川化学工業（株）社製、高酸価型ロジン樹脂、酸価＝２４０ ＫＯＨ ｍｇ／ｇ、軟化温度＝１２５℃）
（＊６）ＫＥ１００（荒川化学工業（株）社製、エステルタイプロジン樹脂、酸価＝１ ＫＯＨ ｍｇ／ｇ、軟化温度＝１２５℃）
（＊７）Ｓ−１４５（ヤスハラケミカル（株）社製、テルペンフェノール樹脂、軟化温度＝１４５℃）
（＊８）Ｉｒｇａｎｏｘ１０１０（チバスペシャリティケミカルズ（株）社製、酸化防止剤）

(* 1) Excellen EUL731 (manufactured by Sumitomo Chemical Co., Ltd., ultra-low density polyethylene; ethylene and α-olefin copolymer, density 0.90 g / cm ³ )
(* 2) Hi-Zex 2100J (Mitsui Chemicals, Inc., adhesive polyolefin; high density polyethylene, density 0.96 g / cm ³ )
(* 3) JER1007K (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol type epoxy resin, epoxy value: 2000 g / eq)
(* 4) YDCN703 (manufactured by Toto Kasei Co., Ltd., novolac type epoxy resin, epoxy value: 230 g / eq)
(* 5) KE604 (manufactured by Arakawa Chemical Industries, Ltd., high acid value type rosin resin, acid value = 240 KOH mg / g, softening temperature = 125 ° C.)
(* 6) KE100 (Arakawa Chemical Industries, Ltd., ester type rosin resin, acid value = 1 KOH mg / g, softening temperature = 125 ° C.)
(* 7) S-145 (Yasuhara Chemical Co., Ltd., terpene phenol resin, softening temperature = 145 ° C)
(* 8) Irganox 1010 (manufactured by Ciba Specialty Chemicals Co., Ltd., antioxidant)

As shown in Tables 1 and 2, in the case of using the resin composition of the present invention, initial adhesiveness by injection molding, long-term durability of the adhesiveness, and high-temperature durability are satisfactory levels. Moreover, the preferable thing as a compound is used, The weight ratio of (1) polyester, (2) polyolefin, (3) epoxy compound, and (4) tackifier is (1) / (2) / (3). By satisfying / (4) = 100 / 10-30 / 5-5 / 5 / 5-20, the above characteristics are further improved, and the mold releasability from the mold and the appearance of the obtained molded product are satisfactory. It becomes.
On the other hand, the resin compositions of Comparative Examples 1 to 4 other than the present invention do not have satisfactory levels of adhesive properties (initial adhesiveness by injection molding, long-term durability of the adhesiveness, and high-temperature durability). Comparative Examples 5 and 6 are evaluation results that seem to be excellent in these characteristics at first glance, but are severely demolded and are not practical compositions.

The resin composition of the present invention has excellent adhesion characteristics and durability characteristics, and further imparts excellent molding characteristics without performing pre-molding treatment such as primer coating on a smooth surface of a metal such as a steel plate or aluminum. It is also possible, and is useful as a polyester-based resin composition for molding and an adhesive for coating metal parts having complicated shapes.

Claims (12)

  (1) Polyester, (2) Polyolefin, (3) Epoxy compound, and (4) Tackifier are (1) / (2) / (3) / (4) = 100 / 1-50 by weight ratio. / 1 to 30/1 to 30, and the polyester (1) is copolymerized with 5 mol% or more and 50 mol% or less of a polyether diol having a number average molecular weight of 500 or more and 4000 or less with respect to all glycol components. The resin composition characterized by the above-mentioned.   The resin composition according to claim 1, wherein the (1) polyester is a crystalline polyester having a melting point of 160 ° C. or higher and 230 ° C. or lower. The resin composition according to claim 1 or 2, wherein the (2) polyolefin is polyethylene or an ethylene copolymer, and the specific gravity is 0.95 g / cm ³ or less.   The resin composition according to any one of claims 1 to 3, wherein the (3) epoxy compound is a bisphenol type epoxy resin or a novolac type epoxy resin.   The resin composition according to any one of claims 1 to 4, wherein the tackifier (4) is a rosin compound.   6. The resin composition according to claim 5, wherein the rosin compound has an acid value of 2 to 300 (KOH mg / g).   The weight ratio of (1) polyester, (2) polyolefin, (3) epoxy compound, and (4) tackifier is (1) / (2) / (3) / (4) = 100 / 10-30. The resin composition according to any one of claims 1 to 6, which is / 5 to 20/5 to 20.   The resin composition according to any one of claims 1 to 7, wherein a surface hardness measured based on ASTM D2240 is 35D or more.   Elongation retention during cutting after heat aging test at 100 ° C. and 1000 hours is 50% or more, elongation retention during cutting after high temperature and high humidity treatment at 80 ° C. and humidity of 500 hours is 50% or more The resin composition according to any one of claims 1 to 8.   The resin composition according to any one of claims 1 to 9, wherein the resin composition is used for metal coating to coat a metal by injection molding.   The metal coating body which coat | covered the resin composition in any one of Claims 1-9 on the metal by injection molding. An adhesive comprising the resin composition according to any one of claims 1 to 9.