JP5308737B2 - Unsaturated polyester resin composition for lamp reflector and molded product thereof, and lamp reflector - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an unsaturated polyester resin composition for a lamp reflector and a molded article thereof, and a lamp reflector, and more particularly to an unsaturated polyester resin composition for a lamp reflector represented by an automotive headlamp, a molded article thereof and a lamp reflector. .

Unsaturated polyester resin molding material (bulk molding compound: BMC) is excellent not only in moldability but also in surface smoothness, dimensional accuracy, heat resistance, mechanical strength, etc. Widely used in office equipment chassis, lamp reflectors typified by automotive headlamps, etc.
Examples of such an unsaturated polyester resin molding material include an unsaturated polyester, a crosslinking agent, polystyrene and a styrene-diene block copolymer and / or a hydrogenated product or a modified product thereof (for example, cited And a polyester containing an unsaturated polyester, a styrene-vinyl acetate block copolymer, a styrene-diene block copolymer and / or a hydrogenated product or a modified product thereof (see, for example, cited document 2). Etc. are known.

By the way, in manufacture of a lamp reflector, after forming and forming a primer layer by applying and curing a primer composition (undercoat) on a molded product (base material) obtained by molding an unsaturated polyester resin molding material, A metal reflective layer is formed by applying a metal coating such as aluminum or zinc on top. Therefore, in addition to the above properties, the unsaturated polyester resin molding material for lamp reflector is also required to give a molded product excellent in the paintability of the primer composition and the adhesion with the primer layer.
However, moldings obtained from conventional unsaturated polyester resin molding materials for lamp reflectors do not have sufficient paintability of the primer composition, resulting in “repellency” of the primer composition, resulting in uniform metal coating. There was a problem that I could not. In addition, even if the primer composition has good paintability, the adhesion with the primer layer is not sufficient, and the performance such as light reflectivity decreases as the lamp reflector has been used, or in some cases from the molded product There was a problem that the primer layer peeled off.

  Here, the paintability of the primer composition to the molded product and the adhesion between the molded product and the primer layer are closely related not only to the composition of the unsaturated polyester resin molding material that gives the molded product, but also to the composition of the primer composition. doing. Therefore, in order to improve the paintability of the primer composition to the molded product and the adhesion between the molded product and the primer layer, the composition of both the unsaturated polyester resin molding material and the primer composition must be considered.

Japanese Patent Publication No. 6-53844 Japanese Patent Publication No. 6-89240

Accordingly, the present invention is excellent in moldability, and in addition to surface smoothness, dimensional accuracy, heat resistance, and mechanical strength, a lamp that provides a molded product excellent in the paintability of the primer composition and the adhesion to the primer layer. An object is to provide an unsaturated polyester resin composition for a reflector.
Another object of the present invention is to provide a molded article and a lamp reflector excellent in surface smoothness, dimensional accuracy, heat resistance and mechanical strength.

  As a result of intensive studies to achieve the above object, the present inventors have determined that a lamp containing a specific unsaturated polyester, a crosslinking agent and a low shrinkage agent at a predetermined ratio when a specific primer composition is used. It has been found that an unsaturated polyester resin composition for reflectors can solve the above problems, and has completed the present invention.

  That is, the present invention comprises (a) an unsaturated polyester obtained by polycondensation of a polyhydric alcohol and an unsaturated polybasic acid; (b) a monomer or prepolymer of diallyl phthalate, and (c) other than diallyl phthalate monomer A low-shrinkage comprising a crosslinking agent comprising a radically polymerizable unsaturated monomer; (d) polystyrene, (e) an acrylic polymer, and (f) a styrene-diene block copolymer and / or a hydrogenated product or a modified product thereof. An unsaturated polyester resin composition for a lamp reflector containing an agent, wherein the content of the low shrinkage agent is 15 to 50 parts by mass with respect to a total of 100 parts by mass of the unsaturated polyester and the crosslinking agent. The mass ratio of d) and (e) is 25:75 to 75:25, and the mass ratio of (d) and (e) to (f) is 10:90 to 50:50. A lamp reflector for unsaturated polyester resin composition characterized Rukoto.

The present invention also provides a molded article obtained by molding the unsaturated polyester resin composition for lamp reflector.
Furthermore, the present invention comprises applying a base material obtained by molding an unsaturated polyester resin composition for a lamp reflector and a primer composition containing 12 to 55% by mass of an acrylic resin on the base material. A lamp reflector comprising: a formed primer layer; and a metal reflective layer formed on the primer layer.

According to the present invention, a lamp capable of providing a molded article having excellent moldability and excellent surface paint smoothness, dimensional accuracy, heat resistance, and mechanical strength, as well as excellent paintability and adhesion to the primer layer. An unsaturated polyester resin composition for a reflector can be provided.
Moreover, according to this invention, the molded object and lamp reflector excellent in surface smoothness, dimensional accuracy, heat resistance, and mechanical strength can be provided.

  The unsaturated polyester resin composition for lamp reflectors of the present invention (hereinafter simply referred to as “unsaturated polyester resin composition”) includes a predetermined unsaturated polyester, a crosslinking agent, and a low shrinkage agent.

The unsaturated polyester used in the present invention is (a) an unsaturated polyester obtained by polycondensation of a polyhydric alcohol and an unsaturated polybasic acid. Such unsaturated polyesters are generally used for molding materials, and can be appropriately selected and used according to desired properties.
The polyhydric alcohol is not particularly limited. For example, ethylene glycol, propylene glycol, neopentyl glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, pentanediol, hexanediol, neopentanediol, hydrogen Bisphenol A, bisphenol A, glycerin and the like can be used. Among these, propylene glycol, neopentyl glycol, and bisphenol A or hydrogenated bisphenol A are preferable from the viewpoints of heat resistance, mechanical strength, moldability, and the like.
The unsaturated polybasic acid is not particularly limited, and for example, maleic anhydride, fumaric acid, citraconic acid, itaconic acid and the like can be used. Among these, maleic anhydride and fumaric acid are preferable from the viewpoints of heat resistance, mechanical strength, moldability, and the like.

The crosslinking agent used in the present invention is composed of (b) a monomer or prepolymer of diallyl phthalate and (c) a radical polymerizable unsaturated monomer other than diallyl phthalate monomer.
(C) The radical polymerizable unsaturated monomer other than the diallyl phthalate monomer is not particularly limited, and for example, styrene monomer, methyl methacrylate, triallyl isocyanurate and the like can be used.
The content of the crosslinking agent composed of (b) and (c) improves the paintability of the primer composition on the molded product, in addition to the workability, polymerizability, shrinkage of the molded product, and the degree of freedom in adjusting the amount. From the viewpoint of making it, it is preferably 30 to 70 parts by mass, more preferably 35 to 65 parts by mass, and most preferably 40 to 60 parts by mass with respect to 100 parts by mass in total of the unsaturated polyester and the crosslinking agent. If the content of the crosslinking agent is less than 30 parts by mass, the unsaturated polyester resin composition may be hard and kneading may be difficult, or the shrinkage of the molded product may be increased. Moreover, when content of a crosslinking agent exceeds 70 mass parts, an unsaturated polyester resin composition may become soft and a moldability may fall, or the heat resistance of a molded product may fall.
Moreover, the mass ratio of (b) and (c) is preferably 5:95 to 25:75, and more preferably 10:90 to 20:80. If the mass ratio of (b) to (c) is too low, the paintability of the primer composition on the molded product may be reduced. Moreover, when the mass ratio of (b) to (c) is too high, the moldability of the unsaturated polyester resin composition may be lowered.

The low shrinkage agent used in the present invention is composed of (d) polystyrene, (e) acrylic polymer, and (f) styrene-diene block copolymer and / or hydrogenated product or modified product thereof.
(D) Polystyrene means a homopolymer of styrene and can be appropriately selected from known polystyrene used as a thermoplastic resin. Among these, polystyrene having a weight average molecular weight of 2,000 to 400,000 is preferable. Examples of such polystyrene include trade name Hiker ST-95 manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name Dialex HF-55 manufactured by Mitsubishi Chemical Corporation, and trade name S Bright T-2 beads manufactured by Showa Denko. Can be mentioned.
(E) Acrylic polymer means a homopolymer of an acrylic monomer, and can be appropriately selected from known acrylic polymers used as thermoplastic resins. Among them, an acrylic polymer having a weight average molecular weight of 25,000 to 550,000 is preferable. Examples of such an acrylic polymer include trade name technopolymer MB manufactured by Sekisui Chemical Co., Ltd., and trade name F320 manufactured by Nippon Zeon Co., Ltd.

(F) Styrene-diene block copolymer and / or hydrogenated product or modified product thereof is SBS or SIS thermoplastic elastomer using polystyrene as a hard segment and polybutadiene or polyisoprene as a soft segment, or the above It is a hydrogenated product obtained by hydrogenating SBS or SIS. As the SEBS-based thermoplastic elastomer or modified product, any of reactive saturated thermoplastic elastomers to which reactivity has been imparted with maleic anhydride or the like can be used. It is also possible to use a mixture of these.
The bonding mode of the styrene-diene block copolymer is roughly classified into a type in which the polystyrene portion and the diene polymer portion take a linear bonding mode, and a radial type in which the diene polymer portions are coupled to each other. Can also be used. The ratio of the styrene part to the diene part is preferably 10% to 50% of styrene. When the ratio of the styrene part is less than 10% and exceeds 50%, it is difficult to obtain a desired shrinkage rate, which is not preferable. The styrene-diene block copolymer preferably has a weight average molecular weight of 100,000 to 400,000.

The content of the low shrinkage agent composed of (d), (e) and (f) is 15 to 50 parts by mass, preferably 20 to 45 parts per 100 parts by mass in total of the unsaturated polyester and the crosslinking agent. Part by mass. When the content of the low shrinkage agent is less than 15 parts by mass, shrinkage of the unsaturated polyester resin composition is increased during curing. Moreover, when content of a low shrinkage agent exceeds 50 mass parts, coloring property will be impaired.
The mass ratio of (d) and (e) is 25:75 to 75:25, preferably 30:70 to 70:30. When the mass ratio of (d) to (e) is too low, the colorability is impaired. On the other hand, if the mass ratio of (d) to (e) is too high, the colorability is good, but the paintability of the primer composition and the adhesion with the primer layer are lowered.
The mass ratio of (d) and (e) to (f) is 10:90 to 50:50, preferably 15:85 to 45:55. When the mass ratio of (d) and (e) to (f) is too low, the shrinkage of the unsaturated polyester resin composition increases during curing and the colorability may not be good. On the other hand, if the mass ratio of (d) and (e) to (f) is too high, the colorability is good, but the shrinkage of the unsaturated polyester resin composition during curing increases.

  The low shrinkage agent composed of (d), (e), and (f) is generally convenient to use after being dissolved or swollen in advance in the above-mentioned crosslinking agent such as styrene, but the crosslinking agent such as styrene. It can be used without being dissolved or swollen.

In addition to the above components, the unsaturated polyester resin composition of the present invention can use a curing agent, a filler, a release agent, a thickener, a fiber reinforcing material, a pigment, and the like as necessary. When using these components, each component is mix | blended with the unsaturated polyester resin composition of this invention by the compounding quantity normally used according to each objective.
As the curing agent, it can be appropriately selected from peroxides and used, for example, t-butyl peroxy octoate, benzoyl peroxide, 1,1-di-t-butyl peroxy-3, 3, 5 -Trimethylcyclohexane, t-butyl peroxyisopropyl carbonate, t-butyl peroxybenzoate, dicumyl peroxide, di-t-butyl peroxide and the like can be used.

The filler is not particularly limited as long as it can be used in the technical field. For example, inorganic materials such as silica, alumina, mica, aluminum hydroxide, calcium carbonate, gypsum, barium sulfate, clay, and talc. Powders can be used.
The release agent is not particularly limited as long as it can be used in the technical field. For example, stearic acid, oleic acid, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, stearic acid Amides, oleic amides, carnauba waxes, silicone oils and synthetic waxes can be used.

The thickener is not particularly limited as long as it can be used in the technical field. For example, a metal compound such as magnesium oxide, magnesium hydroxide, calcium hydroxide, calcium oxide, and an isocyanate compound are used. be able to.
The fiber reinforcing material is not particularly limited as long as it can be used in the technical field. For example, chopped strand glass cut to a fiber length of about 1.5 to 25 mm can be used. Moreover, organic inorganic fibers such as pulp fiber, Tetron (registered trademark) fiber, vinylon fiber, carbon fiber, aramid fiber and wollastonite can also be used.

The unsaturated polyester resin composition of the present invention constituted by the components as described above can be produced by a commonly performed method, for example, by blending the above components and then kneading using a kneader or the like.
The unsaturated polyester resin composition of the present invention thus produced is excellent in moldability and can give a molded product excellent in surface smoothness, dimensional accuracy, heat resistance and mechanical strength. . Here, it does not specifically limit as a shaping | molding method of the unsaturated polyester resin composition of this invention, For example, compression molding, transfer molding, injection molding etc. can be used.
In addition, the molded product obtained by molding the unsaturated polyester resin composition of the present invention is compatible with a specific primer composition described later (that is, paintability of the primer composition and adhesion to the primer layer). Are better. Therefore, this molded product can be used as a base material for a lamp reflector.

The lamp reflector of the present invention includes a base material obtained by molding an unsaturated polyester resin composition, a primer layer formed by applying and drying a specific primer composition on the base material, and a primer layer And a metal reflective layer formed on the substrate.
Here, the primer composition contains an acrylic resin. The acrylic resin is not particularly limited as long as the number average molecular weight is in the range of 100 to 2,000, and those known in the technical field can be used. When the number average molecular weight of the acrylic resin is less than 100, the strength of the primer layer is lowered, and the adhesion of the primer layer to the substrate is lowered. On the other hand, when the number average molecular weight of the acrylic resin exceeds 2,000, the viscosity of the primer composition increases, and the paintability of the primer composition decreases.
Examples of acrylic resins that can be used in the primer composition include pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dipentaerythritol hexaacrylate, and dipentaerythritol pentaacrylate. Examples thereof include resins obtained by homopolymerization or copolymerization of functional monomers.
Content of the acrylic resin in a primer composition is 12-55 mass%. When the content of the acrylic resin is less than 12% by mass, the adhesion of the primer layer to the substrate is lowered. On the other hand, when the content of the acrylic resin exceeds 55% by mass, the viscosity of the primer composition increases and the paintability decreases.

The primer composition may further include a polyester resin. In this case, the content of the polyester resin in the primer composition is 33% by mass or less. When content of a polyester resin exceeds 33 mass%, the adhesiveness of the primer layer with respect to a base material may fall.
The polyester resin that can be used in the primer composition is not particularly limited as long as it is known in the art, and examples thereof include unsaturated polyester resins, vinyl-modified polyester resins, phenol-modified polyester resins, and oil-modified polyesters. Examples thereof include resins and silicone-modified polyester resins.
Moreover, it is preferable that the mass ratio of the acrylic resin and the polyester resin in the primer composition is 100: 0 to 40:60. If the mass ratio of the polyester resin to the acrylic resin is too high, the adhesion of the primer layer to the substrate may be reduced.
The primer composition can contain components such as a curing agent and a solvent. The kind and content of these components are not particularly limited, and may be appropriately adjusted according to the acrylic resin or polyester resin to be used.

The method for applying the primer composition onto the substrate is not particularly limited, and for example, a known method such as an air spray method or an airless spray method can be used. In addition, the drying method may be adjusted as appropriate according to the composition of the primer composition and the coating method.
The thickness of the primer layer may be appropriately set according to the required size of the lamp reflector and the like, but is generally 10 to 30 μm.

The material of the metal reflective layer is not particularly limited as long as it is used for a lamp reflector, and for example, silver, zinc, an alloy mainly composed of silver or zinc, or the like can be used.
The method for forming the metal reflective layer on the primer layer is not particularly limited, and for example, a known method such as a vacuum deposition method can be used.
The thickness of the metal reflective layer may be appropriately set according to the required size of the lamp reflector and the like, but is generally 800 to 2,000 mm.
The lamp reflector of the present invention having such a configuration has excellent compatibility between the base material and the primer composition, and is excellent in surface smoothness, dimensional accuracy, heat resistance and mechanical strength.

Hereinafter, the present invention will be described in detail by way of examples and comparative examples. Of course, the present invention is not limited by the following examples as long as the gist thereof is not exceeded.
The components shown in Table 1 were kneaded at 30 ° C. using a twin-type kneader to obtain unsaturated polyester resin compositions of Examples 1 to 3 and Comparative Examples 1 to 7.

In Table 1, “resin” contains 73% by mass of an unsaturated polyester obtained by polycondensation of a polyhydric alcohol and an unsaturated polybasic acid, and 27% by mass of a styrene monomer as a crosslinking agent. The “acrylic resin” contains 60% by mass of an acrylic polymer and 40% by mass of a styrene monomer as a crosslinking agent.
The following evaluation was performed about these unsaturated polyester resin compositions.

(1) Molding Shrinkage A shrinking disk specified in JIS K6911 5.7 is manufactured, and compression molding is performed under the conditions of a molding temperature of 150 ° C., a molding pressure of 10 MPa, and a molding time of 3 minutes, to JIS K6911 5.7. Based on this, the mold shrinkage was calculated.
(2) Evaluation of molded product Transfer molding was performed under the conditions of a molding temperature of 140 ° C., an injection pressure of 180 kg / cm ² , and a molding time of 1 minute to obtain a transfer molded product (disk shape, diameter 117 mm, thickness 3 mm (uniform)). Produced. The molded product was visually evaluated for appearance leveling and fillability. In these evaluations, those that were very good were indicated by ◎, those that were good by ○, those that were slightly inferior by Δ, and those that were poor by ×.
Further, a wetting tension comparison test on the surface of the molded product was performed according to JIS K6768.

(3) Paintability of primer composition on molded product As the primer composition, one containing 31.5% by mass of an acrylic resin having a number average molecular weight of 500 and 13.5% by mass of a polyester resin was used.
The primer composition is coated on the molded product of (2) to form a primer layer having a thickness of about 3 μm, and a portion with good coating (a portion without repellency) occupying the entire coated portion is visually confirmed, The area ratio was determined.
Further, the primer composition was coated on the molded product of (2) to form a primer layer having a thickness of about 20 μm, and the appearance leveling of the primer layer was visually evaluated. In this evaluation, those that were very good were indicated as ◎, those that were good as ○, those that were slightly inferior as Δ, and those that were poor as ×.
Furthermore, as a comprehensive evaluation of the paintability, ◎ when the area ratio of the part without repelling was 90% or more and the appearance leveling was good, and the area ratio of the part without repelling was 70% or more and less than 90% and the appearance leveling Is good (or very good), the area ratio of the part without cissing is 50% or more to less than 70% and the appearance leveling is inferior (or poor), △, the part without cissing A case where the area ratio was less than 50% and the appearance leveling was inferior (or poor) was determined as x.

(4) Adhesiveness between molded product and primer layer A primer layer having a thickness of about 20 μm is formed on the molded product in the same manner as in (3) above, and a grid defined by JIS K5400 8.5, which is prescribed for adhesion. An eye test (cut interval: 2 mm) was performed, and the evaluation was performed using the evaluation score defined in JIS K5400 8.5, adhesion (Table 18). The evaluation score of 9 or more was evaluated as ◎, 7-8 as ◯, 5-6 as Δ, and 4 or less as X.
The evaluation results are shown in Table 2.

As can be seen from the results in Table 2, the unsaturated polyester resin compositions of Examples 1 to 3 had a small molding shrinkage, and all of the evaluation of the molded product, and the evaluation of paintability and adhesion were good. On the other hand, in the unsaturated polyester resin compositions of Comparative Examples 1 to 7, any of the above evaluation results was not sufficient.
From this result, the unsaturated polyester resin composition of the present invention is excellent in moldability, and in addition to surface smoothness and dimensional accuracy, a molded product excellent in paintability of the primer composition and adhesion to the primer layer. I know you give it.

Next, the following experiment was conducted by changing the composition of the primer composition applied to the molded article of the unsaturated polyester resin composition of the present invention.
The unsaturated polyester resin composition of Example 3 above was used as the unsaturated polyester resin composition of the present invention, and the primer composition having the composition shown in Table 3 was used. And using this primer composition, the applicability | paintability of the primer composition with respect to said (3) molded object and the adhesiveness of (4) molded object and a primer layer were evaluated. The results are shown in Table 3.

As can be seen from the results in Table 3, when the primer compositions of Experiments 1 and 2 were used, both the paintability of the primer composition to the molded product and the adhesion between the molded product and the primer layer were good. However, when the primer compositions of Experiments 3 to 5 were used, any of the above evaluations was not sufficient.
From this result, the paintability of the primer composition to the molded product by the unsaturated polyester resin composition of the present invention and the adhesion between the molded product and the primer layer are not only the composition of the unsaturated polyester resin composition, but also the primer. It is closely related to the composition of the composition, and it is understood that the content of the acrylic resin and the number average molecular weight of the acrylic resin need to be within a predetermined range.

  As can be seen from the above results, the unsaturated polyester resin composition of the present invention is excellent in moldability, and in addition to surface smoothness, dimensional accuracy, heat resistance and mechanical strength, the paintability of the primer composition and the primer A molded product having excellent adhesion to the layer can be provided.

Claims (10)

(A) an unsaturated polyester obtained by polycondensation of a polyhydric alcohol and an unsaturated polybasic acid;
A crosslinking agent comprising (b) a diallyl phthalate monomer or prepolymer, and (c) a radically polymerizable unsaturated monomer other than diallyl phthalate monomer;
An unsaturated polyester resin composition for a lamp reflector, comprising (d) polystyrene, (e) an acrylic polymer, and (f) a low shrinkage agent comprising a styrene-diene block copolymer and / or a hydrogenated product or a modified product thereof. There,
Content of the said low shrinkage agent is 15-50 mass parts with respect to a total of 100 mass parts of the said unsaturated polyester and a crosslinking agent, and the mass ratio of (d) and (e) is 25: 75-75: An unsaturated polyester resin composition for a lamp reflector, wherein the mass ratio of (d) and (e) to (f) is 10:90 to 50:50.   Content of the said crosslinking agent is 30-70 mass parts with respect to a total of 100 mass parts of the said unsaturated polyester and a crosslinking agent, and mass ratio of (b) and (c) is 5: 95-25: The unsaturated polyester resin composition for a lamp reflector according to claim 1, wherein the unsaturated polyester resin composition is 75. The weight average molecular weight of said (e) acrylic polymer is 25,000-550,000, The unsaturated polyester resin composition for lamp reflectors of Claim 1 or 2 characterized by the above-mentioned. A molded product obtained by molding the unsaturated polyester resin composition for a lamp reflector according to any one of claims 1 to 3 . The base material obtained by shape | molding the unsaturated polyester resin composition for lamp reflectors of any one of Claims 1-3, and 12-55 mass of acrylic resins whose number average molecular weights are 100-2,000. A lamp reflector, comprising: a primer layer formed by applying and drying a primer composition containing 2% on the substrate; and a metal reflective layer formed on the primer layer. The lamp reflector according to claim 5 , wherein the primer composition further includes a polyester resin of 33% by mass or less. The polyester resin in the primer composition is at least one selected from the group consisting of unsaturated polyester resins, vinyl-modified polyester resins, phenol-modified polyester resins, oil-modified polyester resins, and silicone-modified polyester resins. The lamp reflector according to claim 6. The lamp reflector according to any one of claims 5 to 7, wherein a mass ratio of the acrylic resin and the polyester resin in the primer composition is 100: 0 to 40:60. The acrylic resin in the primer composition is selected from the group consisting of pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate. The lamp reflector according to any one of claims 5 to 8, wherein the lamp reflector is homopolymerization or copolymerization of a polyfunctional monomer. The thickness of the said primer layer is 10-30 micrometers, The lamp reflector of any one of Claims 5-9 characterized by the above-mentioned.