JP2021011533A - Glass fiber reinforced polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass fiber reinforced polyester resin composition having excellent impact resistance, particularly impact resistance at a low temperature, and further excellent in rigidity, fluidity and hydrolysis resistance. The present invention is a graft-modified ethylene / α-olefin obtained by graft-modifying a polyester resin (A) with 40 to 98% by mass, an unsaturated carboxylic acid satisfying the following requirements (1) to (3) and a derivative thereof. The copolymer (B) is 1 to 50% by mass, and the glass fiber (C) is 1 to 50% by mass [provided that (A) + (B) + (C) = 100% by mass. ] The present invention relates to a glass fiber reinforced polyester resin composition containing. (1) The amount of graft modification is in the range of 0.1 to 2.0% by mass. (2) The MFR (ASTM D1238, 190 ° C., 2.16 kg load) is in the range of 0.1 to 100 g / 10 minutes. (3) The density measured by ASTM D1505 is in the range of 855 to 880 kg / m3. [Selection diagram] None

Description

The present invention relates to a glass fiber reinforced polyester resin composition obtained by blending a graft-modified ethylene / α-olefin copolymer having a specific composition with a polyester resin and a glass fiber.

Thermoplastic polyesters such as polybutylene terephthalate can be used as engineering plastics for some mechanical parts, electric appliance parts, and automobile parts by taking advantage of their excellent performance such as mechanical strength, rigidity, heat resistance, chemical resistance, and oil resistance. Correspondence is planned.

Further, by compounding a fiber reinforcing material with polyester, it is widely used as a material having further excellent mechanical properties and heat resistance. Among the fiber reinforced materials, glass fiber is used in particular.

However, although polyester has the above-mentioned properties, it is inferior in impact resistance as compared with polycarbonate and the like. In addition, it has a drawback of being inferior in hydrolyzability, and a material having more excellent impact strength and hydrolyzability is required.

As a method for improving the impact strength of polyester, a method of blending both an ionomeric terpolymer and a second terpolymer with polyethylene terephthalate, and as a method for improving hydrolyzability, addition of a type that reacts with a terminal carboxyl group. Agents are the mainstream, and for example, epoxy compounds, carbonate compounds, carbodiimide compounds, oxazoline compounds, aziridine compounds, N-glycidylimide and N-glycidylamide are known.

Further, as a method for improving both impact strength and hydrolyzability, a method in which an ethylene-based copolymer, a butadiene-based rubber and an epoxy compound are used in combination has been proposed (see Patent Documents 1 to 5).

Patent Document 2 describes ethylene having 95 to 50% by weight of a thermoplastic polyester resin and 0.01 to 10% by weight of an unsaturated carboxylic acid or its anhydride graft-polymerized as a method for improving impact resistance and having 3 to 3 carbon atoms. It has been proposed to add 0.1 to 10 parts by weight of the polyepoxy compound to the mixture of 5 to 50 parts by weight of the copolymer with α-olefin of 6.

Then, in Comparative Example 1, in Comparative Example 1, 75 parts by weight of polybutylene terephthalate was added to an ethylene-butene-1 copolymer (manufactured by Mitsui Petrochemical Industry Co., Ltd., trade name Toughmer A-4085) and maleic anhydride. Described is a composition containing 25 parts by weight of an acid-grafted maleic anhydride-grafted ethylene-butene-1 copolymer. Reference Example 1 does not describe the density of the ethylene-butene-1 copolymer (manufactured by Mitsui Chemicals, Inc., trade name Toughmer A-4085), but according to the current Mitsui Chemicals brochure, the trade name Toughmer A The density of -4085 is stated to be 885 kg / m ³ .

However, the epoxy compounds used in the above publication often have a problem of lacking viscosity stability because they often lower the viscosity of the polyester resin or increase the viscosity.

Japanese Unexamined Patent Publication No. 58-45253 Japanese Unexamined Patent Publication No. 60-28446 Japanese Unexamined Patent Publication No. 64-16861 Japanese Unexamined Patent Publication No. 1-221448 Japanese Unexamined Patent Publication No. 2011-46950

An object of the present invention is a glass fiber reinforced polyester resin composition which is excellent in impact resistance, particularly impact resistance at low temperature, and further excellent in rigidity, fluidity, and hydrolysis resistance without blending a polyepoxy compound or the like. To provide things.

The present invention is a glass fiber reinforced polyester resin composition shown below.
[1] A graft-modified ethylene / α-olefin copolymer (B) obtained by graft-modifying the polyester resin (A) with 40 to 98% by mass, unsaturated carboxylic acid satisfying the following requirements (1) to (3) and a derivative thereof. ) 1 to 50% by mass, and glass fiber (C) 1 to 50% by mass [However, (A) + (B) + (C) = 100% by mass. ] Is contained in the glass fiber reinforced polyester resin composition.
(1) The amount of graft modification is in the range of 0.1 to 2.0% by mass.
(2) The MFR (ASTM D1238, 190 ° C., 2.16 kg load) is in the range of 0.1 to 100 g / 10 minutes.
(3) The density measured by ASTM D1505 is in the range of 855 to 880 kg / m ³ .
[2] The graft-modified ethylene / α-olefin copolymer (B) has 60 to 97 mol% of structural units derived from ethylene and 3 to 40 mol of structural units derived from α-olefin having 3 to 8 carbon atoms. The glass fiber reinforced polyester resin composition according to [1], which comprises a graft modified product obtained by modifying an ethylene / α-olefin copolymer containing% with an unsaturated carboxylic acid or a derivative thereof.

The glass fiber reinforced polyester resin composition of the present invention can provide a material having excellent moldability (fluidity during molding) and hydrolysis characteristics without impairing the impact strength inherent in the polyester resin, and can be used for automobile parts and electricity. -It is expected to greatly contribute to the expansion of the market for electronic parts and mechanical parts.

Each component of the glass fiber reinforced polyester resin composition according to the embodiment of the present invention will be described in detail below.
[Polyester resin (A)]
As the ester resin (A) which is the main component of the glass fiber reinforced polyester resin composition of the present invention, a known polyester resin having a sufficient molecular weight for forming a molded product can be used without limitation, and usually melt flow. Thermoplastic with a rate (ASTM D1238, 250 ° C., load 325 g) in the range of 0.01-100 g / 10 min, preferably 0.05-50 g / 10 min, more preferably 0.1-30 g / 10 min. It is a polyester resin.

Specifically, the polyester resin (A) according to the present invention is an aliphatic glycol such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol or hexamethylene glycol, or an alicyclic group such as cyclohexanedimethanol. Aromatic dihydroxy compounds such as glycol bisphenol, or dihydroxy compounds selected from two or more of these, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, oxalic acid, succinic acid, adipine. Examples thereof include aliphatic dicarboxylic acids such as acid, sebacic acid and undecadicarboxylic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid, and polyesters formed from a dicarboxylic acid compound selected from two or more of these. ..

The polyester resin (A) according to the present invention may be modified with a small amount of triol, a polyhydroxy compound having a valence of 3 or more such as tricarboxylic acid, a polycarboxylic acid, or the like, as long as it exhibits thermoplasticity.

More specific examples of the polyester resin (A) according to the present invention include polyethylene terephthalate, polybutylene terephthalate, and polyethylene isophthalate / terephthalate copolymers. Of these, polyethylene terephthalate and polybutylene terephthalate are preferable because they have excellent mechanical properties and moldability.

[Graft-modified ethylene / α-olefin copolymer (B)]
The graft-modified ethylene / α-olefin copolymer (B), which is one of the components contained in the glass fiber-reinforced polyester resin composition of the present invention, is a modified product that satisfies the following requirements (1) to (3).
(1) The amount of graft modification is in the range of 0.1 to 2.0% by mass.
(2) The MFR (ASTM D1238, 190 ° C., 2.16 kg load) is in the range of 0.1 to 100 g / 10 minutes.
(3) The density measured by ASTM D1505 is in the range of 855 to 880 kg / m ³ .

<Requirement (1)>
In the graft-modified ethylene / α-olefin copolymer (B) according to the present invention, the graft amount of unsaturated carboxylic acid or its derivative (hereinafter, may be referred to as “modified amount”) is the graft-modified ethylene / α. -With respect to 100% by mass of the olefin copolymer (B), 0.1 to 2.0% by mass, preferably 0.1 to 1.5% by mass, more preferably 0.2 to 1.0% by mass. is there.

If the amount of modification is too small, the impact strength of the obtained molded product may decrease. On the other hand, if the amount of modification is too large, the reaction with the functional groups contained in the polyester resin (A) described above and the glass fiber (C) described later proceeds, and the dispersibility in the polyester resin (A) decreases. As a result, not only the original effect as a modifier of impact strength is not exhibited, but also the fluidity of the polyester resin composition may be lowered.

Examples of the unsaturated carboxylic acids are acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid and nagic acid ^TM (endosis-bicyclo [2,2,1] hepto. -5-ene-2,3-dicarboxylic acid) and the like.

Examples of the derivative of the unsaturated carboxylic acid include acid halide compounds, amide compounds, imide compounds, acid anhydrides and ester compounds of the unsaturated carboxylic acid. Specific examples thereof include malenyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, and glycidyl maleate. Among these, unsaturated dicarboxylic acids or acid anhydrides thereof are suitable, and maleic acid, ^TM nadic acid or acid anhydrides thereof are particularly suitable.

<Requirement (2)>
The graft-modified ethylene / α-olefin copolymer (B) according to the present invention is a polyester resin composition obtained from an MFR (ASTM D1238, 190 ° C., 2.16 kg load) of 0.1 to 100 g / 10 minutes. From the viewpoint of processability and mechanical properties, it is preferably 0.5 to 100 g / 10 minutes, and more preferably 1 to 80 g / 10 minutes.

A graft-modified ethylene / α-olefin copolymer having an MFR of more than 100 g / 10 minutes has a low mechanical strength of the graft-modified ethylene / α-olefin copolymer itself, and the obtained glass fiber-reinforced polyester resin composition is sufficient. There is a risk that the impact strength will not be exhibited, and the graft-modified ethylene / α-olefin copolymer with an MFR of less than 0.1 g / 10 minutes may reduce the fluidity of the obtained glass fiber-reinforced polyester resin composition. There is.

<Requirement (3)>
The graft-modified ethylene / α-olefin copolymer (B) according to the present invention has a density measured by ASTM D1505 in the range of 855 to 880 kg / m ³ , preferably 860 to 870 kg / m ³ .

As the graft-modified ethylene / α-olefin copolymer having a density of more than 880 kg / m ³ , a glass fiber-reinforced polyester resin composition obtained by reducing the mechanical strength of the graft-modified ethylene / α-olefin copolymer is sufficient. On the other hand, when a graft-modified ethylene / α-olefin copolymer having a density of less than 855 kg / m ³ is used, the rigidity of the obtained glass fiber-reinforced polyester resin composition is lowered. There is a risk.

The graft-modified ethylene / α-olefin copolymer (B) according to the present invention has a structure derived from ethylene, although the content of ethylene and α-olefin is not particularly limited as long as the density satisfies the above range. Units are 60-97 mol%, preferably 70-95 mol%, more preferably 75-90 mol%, particularly preferably 80-88 mol% and structural units derived from α-olefins 3-40 mol%, preferably In the range of 5 to 30 mol%, more preferably 10 to 25 mol%, particularly preferably 12 to 20 mol% [Note that the total amount of the structural unit derived from ethylene and the structural unit derived from α-olefin is 100 mol. %. ] Is in the range.

The α-olefin constituting the graft-modified ethylene / α-olefin copolymer (B) according to the present invention usually has 3 or more carbon atoms, preferably 3 to 10 carbon atoms, and more preferably 3 to 8 carbon atoms. -It is an olefin, and propylene, 1-butene, 1-hexene, and 1-octene are more preferable, and 1-butene is particularly preferable because of its availability. The structural unit (mol%) of each comonomer is determined, for example, by analysis of a ¹³ C-NMR spectrum.

Further, the graft-modified ethylene / α-olefin copolymer (B) according to the present invention is a single graft-modified ethylene / α-olefin copolymer as long as the above requirements (1) to (3) are satisfied. It may also be a mixture or composition of graft-modified ethylene / α-olefin copolymers having different physical properties such as density.

The graft-modified ethylene / α-olefin copolymer (B) according to the present invention is particularly located at the graft position of the unsaturated carboxylic acid or its derivative grafted on the following unmodified ethylene / α-olefin copolymer (b). There is no limitation, and an unsaturated carboxylic acid or a derivative thereof may be bonded to any carbon atom of the ethylene / α-olefin copolymer (b).

<Method for producing graft-modified ethylene / α-olefin copolymer (B)>
The graft-modified ethylene / α-olefin copolymer (B) according to the present invention has various known production methods, specifically, an ethylene / α-olefin copolymer (b) [hereinafter, the above-mentioned graft-modified ethylene / α. In order to clarify the difference from the −olefin copolymer (B), it may be referred to as “unmodified ethylene / α-olefin copolymer (b)”. ] Is obtained by grafting the unsaturated carboxylic acid or a derivative thereof in the presence of a radical initiator.

The graft-modified ethylene / α-olefin copolymer (B) according to the present invention can be produced by using various conventionally known methods, for example, the following methods.
(1) A method in which the following unmodified ethylene / α-olefin copolymer (b) is melted and unsaturated carboxylic acid or the like is added to carry out graft copolymerization.
(2) A method in which the following unmodified ethylene / α-olefin copolymer (b) is dissolved in a solvent and unsaturated carboxylic acid or the like is added to carry out graft copolymerization.

The amount of the unsaturated carboxylic acid or its anhydride charged is usually 0.010 to 15 parts by mass, preferably 0.010 to 5 with respect to 100 parts by mass of the unmodified ethylene / α-olefin copolymer (b). It is .0 parts by mass. The amount of the radical initiator used is usually 0.0010 to 1.0 parts by mass, preferably 0.0010 to 0.30 parts by mass with respect to 100 parts by mass of the copolymer before modification.

As the radical initiator, for example, an organic peroxide, an azo compound, a metal hydride, or the like can be used. The radical initiator can be used as it is by mixing it with maleic acid or its anhydride, a copolymer before modification or other components as it is, but it can also be used after being dissolved in a small amount of an organic solvent. .. The organic solvent is not particularly limited as long as it is an organic solvent capable of dissolving the radical initiator.

The reaction temperature in the graft reaction is usually 70 to 200 ° C., preferably 80 to 190 ° C., and a method of reacting for 0.5 to 15 hours, preferably 1 to 10 hours can be mentioned.
Further, a graft modified product can be produced by reacting an unsaturated carboxylic acid or an anhydride thereof with a pre-modified polyolefin in the presence of a radical initiator in the presence of a radical initiator using an extruder or the like. It is usually desirable that this reaction be carried out at a temperature above the melting point of the pre-denatured polyolefin, usually for 0.5-10 minutes.

<Ethylene / α-olefin copolymer (b)>
The density of the unmodified ethylene / α-olefin copolymer (b) used for producing the graft-modified ethylene / α-olefin copolymer (B) according to the present invention is within the above range (855 to 880 kg / m ³ ). An ethylene / α-olefin copolymer, which usually contains 60 to 97 mol% of a structural unit derived from ethylene and 3 to 40 mol% of a structural unit derived from an α-olefin having 3 or more carbon atoms. It is an α-olefin copolymer. The content of the α-olefin having 3 or more carbon atoms is preferably 5 to 30 mol%, more preferably 10 to 25 mol%, and particularly preferably 12 to 20 mol%. When the α-olefin content is in such a range, a modified product having good flexibility and easy handling can be obtained. Moreover, by using this copolymer, it is possible to obtain a glass fiber reinforced polyester resin composition that can provide a molded product having excellent impact strength.

The unmodified ethylene / α-olefin copolymer (b) according to the present invention is a polyester resin composition obtained from MFR (ASTM D1238, 190 ° C., 2.16 kg load) at 0.1 to 100 g / 10 minutes. From the viewpoint of processability and mechanical properties, it is preferably 0.2 to 80 g / 10 minutes, and more preferably 0.3 to 50 g / 10 minutes.

The unmodified ethylene / α-olefin copolymer (b) according to the present invention has different physical properties such as density, even if it is a single polymer, as long as the physical properties such as density satisfy the above range. It may be a mixture or composition of polymers. For example, even if one of the polymers has physical properties such as density outside the above range, a mixture or composition with another polymer may satisfy the above range.

The unmodified ethylene / α-olefin copolymer (b) having the above-mentioned properties is, for example, a vanadium-based catalyst composed of a soluble vanadium compound and an alkylaluminum halide compound, or a zirconium metallocene compound and an organic aluminum oxy compound. It can be prepared by randomly copolymerizing ethylene and an α-olefin having 3 or more carbon atoms in the presence of a zirconium-based catalyst comprising.

As the α-olefin having 3 or more carbon atoms, propylene, 1-butene, 1-hexene and 1-octene are preferable, and 1-butene is particularly preferable, because of its availability. The structural unit (mol%) of each comonomer is determined, for example, by analysis of a ¹³ C-NMR spectrum.

The unmodified ethylene / α-olefin copolymer (b) according to the present invention preferably has a shore A hardness of 20 to 90, more preferably 35 to 60, from the viewpoint of flexibility. For Shore A hardness, a test piece obtained by heating and melting a sample at 190 to 230 ° C. and then press-molding it at a cooling temperature of 15 to 25 ° C. is stored in an environment of 23 ° C. ± 2 ° C. for 72 hours or more. , A value obtained by reading the scale immediately after contact with the needle using an A-type measuring instrument (according to ASTM D2240).

The unmodified ethylene / α-olefin copolymer (b) according to the present invention has a ratio (Mw /) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) measured by gel permeation chromatography (GPC). Mn) is preferably 1.2 to 3.5. By using the unmodified ethylene / α-olefin copolymer (b) in this range, the sticky feeling is suppressed.

The unmodified ethylene / α-olefin copolymer (b) according to the present invention preferably has a glass transition temperature (Tg) in the range of −10 ° C. to −50 ° C. from the viewpoint of mechanical properties. .. This Tg can be determined using a differential scanning calorimetry (DSC).

The method for producing the unmodified ethylene / α-olefin copolymer (b) according to the present invention is not particularly limited, but contains a known catalyst capable of polymerizing the olefin (for example, a solid titanium component and an organic metal compound as main components). It can be produced by copolymerizing ethylene with another α-olefin in the presence of a catalyst (a metallocene catalyst using a metallocene compound as a catalyst component). Preferably, it is obtained by copolymerizing in the presence of a metallocene catalyst.

[Glass fiber (C)]
The glass fiber (C), which is one of the components contained in the glass fiber reinforced polyester resin composition of the present invention, can be used alone or mixed. Further, the glass fiber that can be used is not limited to these, and any filler such as fibrous, plate-like, powder-like, and granular can be mixed and used.

The type of glass fiber is not particularly limited as long as it is generally used for reinforcing the resin, and for example, it can be selected from long fiber type, short fiber type chopped strand, milled fiber and the like. Further, the cross-sectional shape of the glass fiber may be a general circular shape or a non-circular shape such as an eyebrows shape or an oval shape.

When the cross-sectional shape of the glass fiber used in the present invention is circular, the average diameter is preferably in the range of 3 to 50 μm, more preferably 6 to 25 μm. If the average diameter of the glass fibers is less than 5 μm, the glass fibers agglomerate with each other, and the contact area (surface area) with the polyester resin (A) becomes large, so that the fluidity of the glass fiber reinforced polyester resin composition decreases. To do. Further, if it is larger than 50 μm, sufficient rigidity and strength may not be imparted when the glass fiber reinforced polyester resin composition is obtained.

When the cross-sectional shape of the glass fiber is non-circular, the average length of the longest diameter (major diameter) of the cross section is preferably in the range of 3 to 120 μm, more preferably 5 to 60 μm. The average length of the shortest diameter (minor diameter) is preferably 0.3 to 20 μm, more preferably 0.5 to 15 μm. The ratio of major axis to minor axis is preferably in the range of 1.2 to 10, and more preferably in the range of 1.5 to 7.5. When the major axis and the minor axis of the glass fiber having a non-circular cross section satisfy the above relationship, the glass fiber reinforced polyester resin composition is excellent in rigidity, impact strength, and fluidity.

The glass fiber according to the present invention has a fiber length in the range of 1 to 20 mm, preferably 1.5 to 12 mm, and more preferably 2 to 10 mm. By using the glass fiber in the above range, it is excellent in handleability and kneadability with the polyester resin (A), and sufficient rigidity and mechanical strength can be obtained when the glass fiber reinforced polyester resin composition is prepared.

Further, the above-mentioned glass fiber according to the present invention has a surface thereof of a known sizing agent (for example, a coupling agent such as a silane coupling agent or a titanate coupling agent and / or a thermosetting agent such as a urethane resin or an epoxy resin). The surface of the glass fiber may be coated or focused with a resin, a binding agent such as an acrylic resin or an olefin resin). Among them, as the coupling agent, a silane-based coupling agent such as aminosilane or epoxysilane is preferably used. Further, as a binding agent, the epoxy resin is suitable because it has excellent affinity and adhesiveness with the polyester resin (A) which is a matrix resin.

[Other additives]
In addition to the above-mentioned polyester resin (A), graft-modified ethylene / α-olefin copolymer (B) and glass fiber (C), the glass fiber reinforced polyester resin composition according to the present invention may contain, if necessary. Antioxidants, UV absorbers, photoprotectants, phosphite-based heat stabilizers, peroxide decomposition agents, basic auxiliary stabilizers, nucleating agents, plasticizers, lubricants, antioxidants, flame retardants, pigments , Dyes, fillers and other additives can be blended within a range that does not impair the object of the present invention. Further, the glass fiber reinforced polyester resin composition according to the present invention may be blended with other polymers as long as the object of the present invention is not impaired.

[Glass fiber reinforced polyester resin composition]
The glass fiber reinforced polyester resin composition of the present invention contains the polyester resin (A) in an amount of usually 40 to 98% by mass, preferably 50 to 93% by mass, more preferably 60 to 82% by mass, and particularly preferably 75 to 76% by mass. The graft-modified ethylene / α-olefin copolymer (B) is usually 1 to 50% by mass, preferably 2 to 40% by mass, more preferably 3 to 30% by mass, and particularly preferably 4 to 25% by mass. The glass fiber (C) is usually 1 to 50% by mass, preferably 5 to 45% by mass, more preferably 15 to 45% by mass, and particularly preferably 20 to 40% by mass [however, (A) + (B) + (C) = 100% by mass]. By using the polyester resin (A) and the graft-modified ethylene / α-olefin copolymer (B) in such a ratio, a molded product having an excellent balance between the effect of improving impact strength and the fluidity during molding is provided. ..

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.
The polymers used in Examples and Comparative Examples are as follows.

《Polyester resin》
(1) As the polyester resin (A), polybutylene terephthalate having the following physical properties [manufactured by Toray Industries, Inc., trade name PBT, 1401-X06, density = 1310 kg / m ³ , flow length = 103 × 10 ^-3 m, Melt flow rate = 20 g / 10 minutes] (A-1) was used.

<< Graft-modified ethylene / α-olefin copolymer (B) >>
As the graft-modified ethylene / α-olefin copolymer (B), the graft-modified ethylene / α-olefin copolymer obtained by the following production method was used.

<Production of graft-modified ethylene / α-olefin copolymer (B)>
As the unmodified ethylene / α-olefin copolymer (b), an ethylene / 1-butene random copolymer having the following physical properties polymerized using a metallocene catalyst was used.
Ethylene 1-butene random copolymer (b-1)
Content of 1-butene units: 20 mol%
MFR (ASTM D1238, 190 ° C., load 2.16 kg): 0.52 g / 10 minutes Density (ASTM D1505): 861 kg / m ³
Ethylene 1-butene random copolymer (b-2)
Content of 1-butene units: 18 mol%
MFR (ASTM D1238, 190 ° C., load 2.16 kg): 0.5 g / 10 minutes Density (ASTM D1505): 885 kg / m ³

<< Graft-modified ethylene / 1-butene copolymer (B-1) >>
10 kg of the above ethylene / 1-butene random copolymer (b-1), 60 g of maleic anhydride (MAH) and 2,5-dimethyl-2,5-di- (t-butylperoxy) -3-hexyne (day). A solution prepared by dissolving 15 g of Perhexa 25B) manufactured by Oil Co., Ltd. in acetone was blended. Next, the obtained blend was charged from the hopper of a twin-screw extruder having a screw diameter of 30 mm and L / D = 40, and extruded into a strand shape at a resin temperature of 200 ° C., a screw rotation speed of 240 rpm, and a discharge rate of 12 kg / hr. .. The obtained strands were sufficiently cooled and then granulated to obtain a graft-modified ethylene / 1-butene copolymer (B-1). Table 1 shows the physical characteristics of the obtained graft-modified ethylene / 1-butene copolymer.

The degree of modification (maleic anhydride content, expressed as MAH (mass%) in Table 1) of the graft-modified ethylene / 1-butene copolymer (B-1) is assigned to the carbonyl group by FT-IR. Wave number 1780 cm ^-1 Obtained from a separately prepared calibration curve based on peak intensity.

<< Graft-modified ethylene / 1-butene copolymers (B-2) to (B-3) >>
Using the above ethylene / 1-butene copolymer (b-1), maleic anhydride (MAH) and 2,5-dimethyl-2,5-di- (t-butylperoxy) -3-hexine (Nichiyu Co., Ltd.) Co., Ltd., trade name Perhexa 25B) was changed to the MAH amount and compounding amount shown in Table 1, and the graft-modified ethylene / 1-butene copolymer (B-2) was obtained in the same manner as in the above preparation method of B-1. ~ (B-3) was obtained.

<< Graft-modified ethylene / 1-butene copolymer (B-4) >>
Using 7.5 kg of the above ethylene / 1-butene copolymer (b-1) and 2.5 kg of the ethylene / 1-butene copolymer (b-2), maleic anhydride (MAH) and 2.5-dimethyl -2,5-Di- (t-butylperoxy) -3-hexine (manufactured by Nichiyu Co., Ltd., trade name Perhexa 25B) was changed to the MAH amount and compounding amount shown in Table 1, except for the above B-1. A graft-modified ethylene / 1-butene copolymer (B-4) was obtained in the same manner as in the preparation method.
The various physical characteristics of the obtained graft-modified ethylene / 1-butene copolymers (B-1) to (B-4) were measured by the following methods and are shown in Table 1.

(Preparation of press sheet for measurement)
A pressure sheet was formed at 10 MPa using a hydraulic heat press machine manufactured by Shinto Metal Industry Co., Ltd. set at 200 ° C. In the case of a 0.5 to 3 mm thick sheet (spacer shape: 240 x 240 x 2 mm thick plate with 80 x 80 x 0.5 to 3 mm, 4 pieces), the residual heat is about 5 to 7 minutes, and 1 at 10 MPa. After pressurizing for ~ 2 minutes, another hydraulic heat press machine manufactured by Shinto Metal Industry Co., Ltd., which was set at 20 ° C., was used to compress at 10 MPa and cool for about 5 minutes to prepare a sample for measurement. A brass plate having a thickness of 5 mm was used as the hot plate. The samples prepared by the above method were used for various physical property evaluation samples.
(MFR)
The melt flow rate (MFR) was measured under the condition of 230 ° C. and 2.16 kg load.
(density)
Measured according to ASTM D1505.

[Example 1]
<< Production of polyester resin composition >>
A dry blend was prepared by mixing 68 parts by mass of polybutylene terephthalate (A-1) and 2 parts by mass of the graft-modified ethylene / 1-butene copolymer (B-1) using a Henchel mixer.

Next, while charging this dry blend product into the main inlet of a twin-screw extruder (L / D = 40, 30 mmφ) set at 250 ° C., glass fiber [manufactured by Nippon Electric Glass Co., Ltd.] was introduced from the sub inlet. , GF, chopped strand type, circular cross section, fiber system 10 μm, epoxy converging agent T-127H] (C-1) 30 parts by mass [(A-1) + (B-1) + (C-1) total 100 Mass%] was sequentially added to prepare pellets of the glass fiber reinforced polyester resin composition. At this time, the screw was extruded at a screw rotation speed of 200 rpm and a discharge rate of 10 kg / hr.

The obtained pellets of the glass fiber reinforced polyester resin composition were dried at 100 ° C. for one day and night, and then injection molded to prepare a test piece for a physical characteristic test. Subsequently, the physical properties of the glass fiber reinforced polyester resin composition were evaluated by the following method.

(1) Bending test The flexural modulus (FM; kg / cm ² ) was measured according to ASTM D790 using a test piece having a thickness of 1/8 ”. The state of the test piece was prepared at 23 ° C. in a dry state. The temperature was 2 days.

(2) Izod Impact Test Using a test piece with a thickness of 1/8 ", the impact strength of the notched Izod was measured at 23, 0, -20, and -40 ° C according to ASTM D256.

(3) Fluidity Injection molding into a mold with a 3.8 mmφ semicircular spiral groove using an injection molding machine with a cylinder temperature of 250 ° C, an injection pressure of 100 MPa, and a mold temperature of 80 ° C with a 50t mold clamping force. And the flow distance was measured.

(4) Hydrolysis characteristics (measured only in some examples and some comparative examples)
A test piece having a thickness of 1/8 ”is injection-molded, and the obtained dumbbell piece is treated under the conditions of a temperature of 95 ° C. and a humidity of 100% RH for 0 hours (untreated) and 168 hours, and then has a tensile strength according to ASTM D638. , The elongation at break was measured, and the percentage of the value obtained by dividing the measured value after the treatment for 168 hours by the measured value of the untreated product was obtained and used as the retention rate (%) as an index of the hydrolysis characteristics.
The evaluation results are shown in Table 1.

[Examples 2 to 7]
The graft-modified ethylene / 1-butene copolymer (B-1) used in the glass fiber-reinforced polyester resin composition used in Example 1 was obtained from the graft-modified ethylene / 1-butene copolymer (B-1) obtained by the above production method. Examples except that the amounts of polybutylene terephthalate (A-1) and the graft-modified ethylene / 1-butene copolymer are changed to the amounts shown in Table 1 while changing to B-2) to (B-4). The same procedure as in No. 1 was carried out to obtain a glass fiber reinforced polyester resin composition.
Table 1 shows the evaluation results of the physical properties.

[Comparative Example 1]
Instead of the glass fiber reinforced polyester resin composition used in Example 1, the graft-modified ethylene / 1-butene copolymer (B-1) was not blended, and polybutylene terephthalate (A-1) and glass fiber (C) were not blended. A glass fiber reinforced polyester resin composition was obtained in the same manner as in Example 1 except that -1) was used.
Table 1 shows the evaluation results of the physical properties.

[Comparative Examples 2 and 3]
Instead of the glass fiber reinforced polyester resin composition used in Example 1, instead of the graft-modified ethylene / 1-butene copolymer (B-1), an ethylene / acrylic elastomer [Alchema; LOTADER (registered trademark)) A glass fiber reinforced polyester resin composition was obtained in the same manner as in Example 1 except that GMA AX8900] (E-1) was used.
Table 1 shows the evaluation results of the physical properties.

[Comparative Examples 4 and 5]
Instead of the glass fiber reinforced polyester resin composition used in Example 1, instead of the graft-modified ethylene / 1-butene copolymer (B-1), a core-shell type elastomer [Dow: paraloid EXL-2620 (E-). A glass fiber reinforced polyester resin composition was obtained in the same manner as in Example 1 except that 2) was used.
Table 1 shows the evaluation results of the physical properties.

From the results in Table 1, the following became clear.
In comparison between Examples 1 to 7 and Comparative Examples 1 to 5, the impact resistance of the glass fiber reinforced polyester resin composition, particularly the low temperature impact resistance, was significantly improved by using the graft-modified ethylene / α-olefin copolymer. You can see that.

In the comparison between Examples 3 and 4 and Comparative Examples 2 and 3, a glass fiber reinforced polyester using an ethylene / acrylic elastomer (E-1) by using a graft-modified ethylene / α-olefin copolymer was used. It can be seen that the hydrolysis resistance is superior to that of the resin composition.

Claims (2)

Polyester resin (A) 40-98% by mass,
1 to 50% by mass of a graft-modified ethylene / α-olefin copolymer (B) graft-modified with an unsaturated carboxylic acid and a derivative thereof that satisfy the following requirements (1) to (3), and
Glass fiber (C) 1 to 50% by mass [However, (A) + (B) + (C) = 100% by mass. ] Is contained in the glass fiber reinforced polyester resin composition.
(1) The amount of graft modification is in the range of 0.1 to 2.0% by mass.
(2) The MFR (ASTM D1238, 190 ° C., 2.16 kg load) is in the range of 0.1 to 100 g / 10 minutes.
(3) The density measured by ASTM D1505 is in the range of 855 to 880 kg / m ³ . The graft-modified ethylene / α-olefin copolymer (B) contains 60 to 97 mol% of structural units derived from ethylene and 3 to 40 mol% of structural units derived from α-olefin having 3 to 8 carbon atoms. The glass fiber reinforced polyester resin composition according to claim 1, which comprises a graft modified product obtained by modifying the ethylene / α-olefin copolymer containing the copolymer with an unsaturated carboxylic acid or a derivative thereof.