Thermoplastic resin composition, resin molding and method for producing resin molding

Abstract

To provide a thermoplastic resin composition that can give a resin molding containing highly dispersed reinforced fibers and having high strength.SOLUTION: A thermoplastic resin composition contains a thermoplastic resin A having a bisphenol structure having introduced thereinto, and a thermoplastic resin B having no bisphenol structure introduced thereinto.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a thermoplastic resin composition, a resin molded article, and a method for producing a resin molded article. [Background technology]

[0002] 2. Description of the Related Art Fiber-reinforced resin materials, which have their strength improved by mixing reinforcing fibers such as glass fibers, carbon fibers, and cellulose fibers with thermoplastic resins, are widely used as materials for resin molded articles. In order to increase the strength of resin moldings obtained using fiber-reinforced resin materials, it is important to thoroughly disperse the reinforcing fibers in the moldings. For this reason, in order to increase the dispersibility of the reinforcing fibers, a method is generally used in which a raw material (master batch) in which the reinforcing fibers are mixed with the thermoplastic resin is fed into a molding machine.

[0003] On the other hand, from the viewpoint of reducing manufacturing costs, a method of feeding reinforcing fibers and thermoplastic resin into a molding machine without mixing them in advance has been considered. For example, Patent Document 1 proposes an injection molding machine that includes a resin supplying section that supplies a resin raw material into a cylinder, and a fiber supplying section that is provided forward of the resin supplying section and supplies reinforcing fibers into the cylinder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-199200 A Summary of the Invention [Problem to be solved by the invention]

[0005] The injection molding machine described in Patent Document 1 is advantageous in terms of reducing manufacturing costs because the resin and reinforcing fibers are mixed inside the cylinder, but there is room for improvement in the dispersion of the reinforcing fibers in the obtained molded body, and ultimately in the strength of the molded body. In view of the above circumstances, an object of the present disclosure is to provide a thermoplastic resin composition that can give a resin molded article having excellent reinforcing fiber dispersion and strength, a resin molded article obtained using this thermoplastic resin composition, and a method for producing a resin molded article. [Means for solving the problem]

[0006] Means for solving the above problems include the following embodiments. <1> A thermoplastic resin composition comprising a thermoplastic resin A having a bisphenol structure introduced therein and a thermoplastic resin B having no bisphenol structure introduced therein. <2> Thermoplastic resin A is polypropylene having a bisphenol structure introduced therein, and thermoplastic resin B is polypropylene. <1> The thermoplastic resin composition according to claim 1. <3> The weight average molecular weight of thermoplastic resin A is smaller than the weight average molecular weight of thermoplastic resin B. <1> or <2> The thermoplastic resin composition according to claim 1. <4> The melt flow rate of thermoplastic resin A at 180°C and a load of 2.16 kg is greater than the melt flow rate of thermoplastic resin B at 180°C and a load of 2.16 kg. <1> ~ <3> The thermoplastic resin composition according to any one of claims 1 to 10. <5> <1> ~ <4> 13. A resin molded product comprising the thermoplastic resin composition according to any one of claims 1 to 12 and reinforcing fibers. <6> The reinforcing fibers are glass fibers. <5> The resin molded article according to claim 1. <7> <1> ~ <4> 13. A method for producing a resin molded product, comprising: kneading the thermoplastic resin composition according to any one of claims 1 to 12 with reinforcing fibers to obtain a kneaded mixture; and molding the kneaded mixture. Effect of the Invention

[0007] According to the present disclosure, there are provided a thermoplastic resin composition that can give a resin molded article having excellent reinforcing fiber dispersion and strength, a resin molded article obtained using this thermoplastic resin composition, and a method for producing a resin molded article. [Brief description of the drawings]

[0008] [Figure 1] 1 is a photograph of the surface of a test piece prepared in an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the components (including element steps, etc.) are not essential unless otherwise specified or considered to be obviously essential in principle. The same applies to the numerical values ​​and their ranges, and they do not limit the present disclosure.

[0010] In the present disclosure, the term "step" refers not only to an independent step, but also to a step that cannot be clearly distinguished from other steps, as long as the purpose of the step is achieved. In the present disclosure, a numerical range indicated using "~" includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the present disclosure, the content of each component in a composition means, when multiple substances corresponding to each component are present in the composition, the total amount of those multiple substances present in the composition, unless otherwise specified.

[0011] <Thermoplastic resin composition> The thermoplastic resin composition according to the present disclosure contains a thermoplastic resin A having a bisphenol structure introduced therein, and a thermoplastic resin B having no bisphenol structure introduced therein.

[0012] By using the above-mentioned thermoplastic resin composition, a resin molding having excellent dispersion and strength of the reinforcing fibers can be obtained even when the reinforcing fibers are not mixed with the resin in advance. The reason for this is not necessarily clear, but is presumed to be as follows.

[0013] In the process of introducing a bisphenol structure, the molecular chain of the thermoplastic resin A contained in the thermoplastic resin composition is cut by a radical initiator. As a result, the molecular weight of the thermoplastic resin is reduced and the flowability is improved. On the other hand, it is believed that the introduction of the bisphenol structure affects the crystallinity of the thermoplastic resin, so that sufficient matrix strength is maintained. Furthermore, by including thermoplastic resin B without a bisphenol structure in addition to thermoplastic resin A, uneven distribution of reinforcing fibers in the resin molding is suppressed compared to the case of using only thermoplastic resin A. This is thought to be because, when only thermoplastic resin A is used, the fluidity of the resin composition is too high and the reinforcing fibers are easily separated from the resin during kneading or molding, whereas by using thermoplastic resin B in combination, the fluidity of the resin composition is controlled within an appropriate range and separation of the reinforcing fibers is suppressed.

[0014] In the present disclosure, "thermoplastic resin A having a bisphenol structure introduced" refers to the entire thermoplastic resin that has undergone the process of introducing a bisphenol structure. Therefore, a state that includes molecules to which a bisphenol structure has not been introduced in the process of introducing a bisphenol structure also falls under "thermoplastic resin A having a bisphenol structure introduced." In the present disclosure, the term "bisphenol structure" refers to a structure derived from a bisphenol compound described below, for example, a structure in which two benzene rings are bonded via a divalent hydrocarbon group.

[0015] (Thermoplastic resin A) Examples of thermoplastic resins that can be used as the base for thermoplastic resin A include polyolefins such as polypropylene and polyethylene, polyvinyl chloride, polyester, polystyrene, polyvinyl acetate, polyurethane, ABS resin (acrylonitrile-butadiene-styrene copolymer resin), acrylic resin, polyamide, polyacetal, polycarbonate, etc. Thermoplastic resins may be homopolymers obtained from one type of polymerization component, or copolymers obtained from two or more types of copolymerization components. Among these, polypropylene is preferred because it has an excellent balance between mechanical strength and ductility and does not contain any substituent that may cause a side reaction with the bisphenol compound. The thermoplastic resin A contained in the thermoplastic resin composition may be of only one type, or of two or more types.

[0016] There is no particular limitation on the method for obtaining the thermoplastic resin A having a bisphenol structure introduced therein. For example, a reaction between a base thermoplastic resin and a bisphenol compound may be caused using a radical initiator.

[0017] The bisphenol compound used for introducing the bisphenol structure is not particularly limited as long as it is a compound having two hydroxyphenyl groups in the molecule, and examples thereof include bisphenol A, bisphenol B, bisphenol AD, bisphenol F, bisphenol S, bisphenol AP, bisphenol BP, etc. Among these, in consideration of the burden on the environment, bisphenol compounds such as bisphenol A that do not use VOC-regulated substances (acetaldehyde, formaldehyde, etc.) as raw materials are preferred. VOC stands for Volatile Organic Compounds. Substances subject to VOC regulations are substances regulated by the Air Pollution Control Act, and are defined as organic compounds that are in the form of gas when emitted or dispersed into the atmosphere, excluding methane, chlorodifluoromethane, tetrafluoroethane, fluoroethane, difluoroethane, pentafluoropropane, pentafluoropropane, and decafluoropentane. The bisphenol compound used for introducing the bisphenol structure may be one kind or two or more kinds.

[0018] The amount of the bisphenol compound used to introduce the bisphenol structure is preferably 0.01 parts by mass to 20 parts by mass, more preferably 0.025 parts by mass to 10 parts by mass, and even more preferably 0.05 parts by mass to 1 part by mass, when the total amount of the thermoplastic resin and the bisphenol compound is 100 parts by mass. When the amount of the bisphenol compound is 0.01 part by mass or more, the balance between the flowability of the obtained thermoplastic resin composition and the mechanical strength of the resin molded product is good. When the amount of the bisphenol compound is 20 parts by mass or less, the inhibition of the formation of a crystal structure of the thermoplastic resin due to the bisphenol structure is suppressed.

[0019] When a radical initiator is used for introducing a bisphenol structure, the type of the radical initiator is not particularly limited. Although the mechanism by which a bisphenol structure is introduced into a thermoplastic resin by using a radical initiator is not necessarily clear, it is believed that the radical generated by decomposition of the radical initiator generates a carbon radical on the thermoplastic resin, and this carbon radical reacts with a benzene ring on the bisphenol compound, resulting in the introduction of a bisphenol structure into the thermoplastic resin. However, in the present disclosure, the introduction mechanism is not limited to the above mechanism.

[0020] When the bisphenol structure is introduced by melt-kneading a thermoplastic resin and a bisphenol compound, the radical initiator is preferably one that decomposes at the temperature during melt-kneading to generate radicals. For example, a radical initiator having a half-life of 1 minute at a temperature of 130°C to 270°C is preferred.

[0021] Specific examples of radical initiators include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; peroxyketals such as n-butyl 4,4-bis(t-butylperoxy)valerate and 2,2-bis(t-butylperoxy)butane; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, di-i-propylbenzene hydroperoxide, p-menthane hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide; di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, and 2,5-dimethyl Examples of the peroxyesters include dialkyl peroxides such as 2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)hexene-3; peroxyesters such as t-butylperoxyacetate, t-butylperoxyoctoate, t-butylperoxy3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, and di-t-butyldiperoxyisophthalate; and peroxyesters such as 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxymaleic acid, and t-butylperoxyi-propylcarbonate. Among these, dialkyl peroxides are preferred, and di-t-butylperoxide, t-butylcumylperoxide, and dicumylperoxide are more preferred.

[0022] The amount of the radical initiator used to introduce the bisphenol structure is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, when the total amount of the thermoplastic resin and the bisphenol compound is 100 parts by mass. When the amount of the radical initiator is 0.1 parts by mass or more, a sufficient amount of bisphenol structure can be introduced into the thermoplastic resin, and the effect of improving the flowability due to the reduction in the molecular weight of the thermoplastic resin A can be sufficiently obtained. When the amount of the radical initiator is 5 parts by mass or less, the molecular weight of the thermoplastic resin A does not decrease too much, and the strength of the resin molded article is sufficiently ensured.

[0023] The thermoplastic resin A may have, in addition to the bisphenol structure, a functional group such as an acid anhydride group, an epoxy group, or an amino group introduced therein. The type of functional group is not particularly limited and can be selected according to the type of reinforcing fiber. For example, by introducing a hydrophilic functional group such as an acid anhydride group or an epoxy group, the affinity with the reinforcing fiber tends to be improved and the dispersibility tends to be improved. Among them, a maleic anhydride group is preferable because it is relatively inexpensive and has little effect on the flowability and mechanical strength of the thermoplastic resin composition.

[0024] When a functional group is introduced into the thermoplastic resin A, the method is not particularly limited, and the functional group can be introduced into the thermoplastic resin A by a known method. For example, a mixture containing the thermoplastic resin A and the compound having a functional group may be kneaded while being heated.

[0025] When a functional group is introduced into the thermoplastic resin A, the introduction of the bisphenol structure and the introduction of the functional group may be carried out simultaneously. For example, as shown in the examples described later, a mixture containing a thermoplastic resin that serves as a base for thermoplastic resin A, a bisphenol compound, a radical initiator, and a compound having a functional group may be kneaded while being heated.

[0026] The weight average molecular weight of the thermoplastic resin A is preferably 50,000 to 200,000. When the weight average molecular weight of the thermoplastic resin A is 200,000 or less, the effect of improving the flowability of the thermoplastic resin composition can be sufficiently obtained. When the weight average molecular weight of the thermoplastic resin A is 50,000 or more, the strength of the obtained resin molded article is sufficiently ensured.

[0027] In the present disclosure, the weight average molecular weight of a thermoplastic resin is a weight average molecular weight calculated as polystyrene, measured by gel permeation chromatography (GPC).

[0028] The melt flow rate of the thermoplastic resin A at 180° C. under a load of 2.16 kg is preferably 50 g / min to 300 g / min. When the thermoplastic resin A has a melt flow rate of 50 g / min or more at 180° C. under a load of 2.16 kg, the effect of improving the flowability of the thermoplastic resin composition can be sufficiently obtained. When the melt flow rate of the thermoplastic resin A at 180° C. under a load of 2.16 kg is 300 g / min or less, the strength of the resulting resin molded article is sufficiently ensured.

[0029] In this disclosure, the melt flow rate of a thermoplastic resin at 180°C and a load of 2.16 kg is measured using a melt flow indexer under conditions of 180°C and a load of 2.16 kg in accordance with JIS K7210-1 (2014).

[0030] (Thermoplastic resin B) Examples of the thermoplastic resin B include polyolefins such as polypropylene and polyethylene, polyvinyl chloride, polyester, polystyrene, polyvinyl acetate, polyurethane, ABS resin, acrylic resin, polyamide, polyacetal, polycarbonate, etc. The thermoplastic resin may be a homopolymer obtained from one type of polymerization component, or a copolymer obtained from two or more types of copolymerization components. Among these, polypropylene is preferred because it has an excellent balance between mechanical strength and ductility and does not contain any substituent that may cause a side reaction with the bisphenol compound. The thermoplastic resin B contained in the thermoplastic resin composition may be of only one type, or of two or more types.

[0031] From the viewpoint of affinity between the resins, it is preferable that the thermoplastic resin B is the same type as the thermoplastic resin A. For example, it is preferable that the thermoplastic resin B and the thermoplastic resin A are both polypropylene.

[0032] From the viewpoint of appropriately adjusting the fluidity of the thermoplastic resin composition, the weight average molecular weight of the thermoplastic resin B is preferably larger than the weight average molecular weight of the thermoplastic resin A.

[0033] The weight average molecular weight of the thermoplastic resin B is preferably more than 200,000 and 500,000 or less. When the weight average molecular weight of the thermoplastic resin B is 500,000 or less, the flowability of the thermoplastic resin composition is sufficiently ensured. When the weight average molecular weight of thermoplastic resin B is greater than 200,000, the fluidity of the thermoplastic resin composition obtained by mixing it with thermoplastic resin A can be easily adjusted to a desired range.

[0034] From the viewpoint of appropriately adjusting the fluidity of the thermoplastic resin composition, it is preferable that the melt flow rate of thermoplastic resin B at 180° C. and a load of 2.16 kg is smaller than the melt flow rate of thermoplastic resin A at 180° C. and a load of 2.16 kg.

[0035] The melt flow rate of thermoplastic resin B at 180° C. under a load of 2.16 kg is preferably 5 g / min to 25 g / min. When the melt flow rate of thermoplastic resin B at 180° C. under a load of 2.16 kg is 5 g / min or more, the flowability of the thermoplastic resin composition is sufficiently ensured. When the melt flow rate of thermoplastic resin B at 180° C. under a load of 2.16 kg is 25 g / min or less, the fluidity of the thermoplastic resin composition obtained by mixing it with thermoplastic resin A can be easily adjusted to a desired range.

[0036] The thermoplastic resin B may have a functional group such as an acid anhydride group, an epoxy group, or an amino group introduced therein. The type of functional group is not particularly limited and can be selected according to the type of reinforcing fiber. For example, by introducing a hydrophilic functional group such as an acid anhydride group or an epoxy group, the affinity with the hydrophilic reinforcing fiber tends to be improved and the dispersibility tends to be improved. Among them, the maleic anhydride group is preferred because it is relatively inexpensive and has little effect on the flowability and mechanical strength of the thermoplastic resin composition. When a functional group is introduced into the thermoplastic resin B, the method is not particularly limited and can be performed by a known method. For example, a mixture containing the thermoplastic resin B and a compound having a functional group may be kneaded while being heated.

[0037] The ratio of thermoplastic resin A to thermoplastic resin B in the thermoplastic resin composition is not particularly limited. From the viewpoint of obtaining a sufficient effect of improving the dispersion of the reinforcing fibers, the content of thermoplastic resin A in the total of thermoplastic resin A and thermoplastic resin B is preferably 10 mass% or more, more preferably 20 mass% or more, and even more preferably 30 mass% or more. From the viewpoint of appropriately adjusting the fluidity of the thermoplastic resin composition and suppressing uneven distribution of the reinforcing fibers in the resin molded body, the content of thermoplastic resin A in the total of thermoplastic resin A and thermoplastic resin B is preferably 80 mass% or less, more preferably 70 mass% or less, and even more preferably 60 mass% or less.

[0038] If necessary, the thermoplastic resin composition may contain various additives, such as colorants, weather resistance agents, and flame retardants. The thermoplastic resin composition may or may not contain reinforcing fibers. Details and preferred embodiments of the reinforcing fibers are the same as those of the reinforcing fibers contained in the resin molded product described later.

[0039] The melt flow rate of the thermoplastic resin composition at 180° C. under a load of 2.16 kg is preferably 20 g / min to 80 g / min. When the thermoplastic resin composition has a melt flow rate of 20 g / min or more at 180° C. under a load of 2.16 kg, the reinforcing fibers can be dispersed more uniformly, and uneven distribution of the reinforcing fibers in the resin molding is suppressed. When the melt flow rate of the thermoplastic resin composition is 80 g / min or less at 180° C. under a load of 2.16 kg, the reinforcing fibers are easily opened and the dispersibility is excellent.

[0040] The melt flow rate of the thermoplastic resin composition can be adjusted by the conditions for introducing the bisphenol structure when obtaining the thermoplastic resin A, the compounding ratio of the thermoplastic resin A and the thermoplastic resin B, and the like.

[0041] <Resin molded body> The resin molded article of the present disclosure includes the above-mentioned thermoplastic resin composition and reinforcing fibers. More specifically, the resin molded article is obtained by molding a mixture of the above-mentioned thermoplastic resin composition and reinforcing fibers.

[0042] The type of reinforcing fiber contained in the resin molded product is not particularly limited and can be selected according to the application of the resin molded product. For example, glass fiber, carbon fiber, cellulose fiber, resin fiber, etc. may be mentioned. If necessary, the reinforcing fiber may be subjected to a chemical or physical surface treatment. The reinforcing fibers contained in the resin molding may be of one type or two or more types.

[0043] The fiber diameter of the reinforcing fibers is preferably 1 μm to 30 μm. When the fiber diameter of the reinforcing fibers is 1 μm or more, the reinforcing fibers can sufficiently improve the strength of the resin molding. When the fiber diameter of the reinforcing fibers is 30 μm or less, a sufficient contact area between the reinforcing fibers and the surrounding resin can be obtained, and the strength improvement effect can be sufficiently obtained. The above fiber diameter of the reinforcing fibers is the fiber diameter in an opened state.

[0044] The fiber length of the reinforcing fibers is preferably 0.1 mm to 100 mm. When the fiber length of the reinforcing fibers is 0.1 mm or more, the reinforcing fibers can sufficiently improve the strength of the resin molding. When the fiber length of the reinforcing fibers is 100 mm or less, the reinforcing fibers are excellently dispersible in the resin molding, and the strength improvement effect can be sufficiently obtained.

[0045] The content of the reinforcing fibers in the resin molded body is preferably 1% by mass to 70% by mass, more preferably 10% by mass to 60% by mass, and even more preferably 20% by mass to 50% by mass of the entire resin molded body. When the content of the reinforcing fibers is 1% by mass or more, the effect of improving the strength of the resin molded body by the reinforcing fibers is sufficiently obtained. When the content of the reinforcing fibers is 70% by mass or less, the flowability of the thermoplastic resin composition is sufficiently ensured, and good moldability is maintained.

[0046] When the thermoplastic resin composition contains reinforcing fibers, the entire amount of the reinforcing fibers contained in the obtained resin molded product may be contained in the thermoplastic resin composition, or a part of the reinforcing fibers may be contained in the thermoplastic resin composition and the rest may be added later. For example, a part of the reinforcing fibers may be mixed with the thermoplastic resin during the injection molding process.

[0047] The resin molded article obtained by using the above-mentioned thermoplastic resin composition and reinforcing fibers has excellent mechanical strength, and is therefore suitable for use in applications requiring a high level of mechanical strength, such as electrical and electronic equipment parts and automotive interior and exterior parts.

[0048] Examples of automobile interior and exterior parts include automobile exterior panels, doors, door trims, quarter trims, bumpers, instrument panels, front-end modules, airbag peripheral parts, luggage peripheral parts, cockpits, fan shrouds, radiator cooling fans, reserve tanks, automobile wheel covers, housings, windshield washer fluid tanks, spoilers, bonnets, fuel pump housings, air cleaners, slot bodies, intake manifolds, heater housings, bonnets, pillars, safety belt parts, etc. Among these, the material is preferably used as automobile exterior panels, bumpers, instrument panels, doors, pillars, or airbag peripheral parts that require a high level of mechanical strength.

[0049] <Method of manufacturing resin molded body> The method for producing a resin molded article according to the present disclosure includes a step of kneading the above-described thermoplastic resin composition with reinforcing fibers to obtain a kneaded mixture, and a step of molding the kneaded mixture.

[0050] The details and preferred embodiments of the reinforcing fibers used in the above method are the same as those of the reinforcing fibers contained in the resin molded product described above. The reinforcing fibers used in the above method may be in a state in which they are premixed with the resin or in a state in which they are not premixed with the resin. From the viewpoint of reducing production costs, it is preferable that the reinforcing fibers are not premixed with the resin.

[0051] In the above-mentioned method, a thermoplastic resin composition containing a thermoplastic resin A having a bisphenol structure introduced therein and a thermoplastic resin B having no bisphenol structure introduced therein is used, so that even if reinforcing fibers that have not been mixed with the resin in advance are used, a resin molded product having excellent dispersion of the reinforcing fibers and strength can be obtained.

[0052] The above method can be carried out by known processing methods such as injection molding, extrusion molding, blow molding, hollow molding, rotational molding, transfer molding, heat press molding, tube molding, etc. Among these, injection molding or extrusion molding is preferred from the viewpoint of ensuring the degree of freedom in the molding cycle and the shape of the molded product.

[0053] In the above method, the step of kneading the thermoplastic resin composition and the reinforcing fibers (kneading step) may be performed by feeding the thermoplastic resin composition and the reinforcing fibers in a mixed state into a kneading device (cylinder, etc.), or by feeding the thermoplastic resin composition and the reinforcing fibers separately into a kneading device. The kneading conditions are not particularly limited, and can be performed under known conditions.

[0054] In the above method, the thermoplastic resin A having a bisphenol structure introduced therein and the thermoplastic resin B having no bisphenol structure introduced therein may be mixed and charged into the kneading device, or the thermoplastic resin A having a bisphenol structure introduced therein and the thermoplastic resin B having no bisphenol structure introduced therein may be separately charged into the kneading device. That is, the preparation of the thermoplastic resin composition (mixing of the thermoplastic resin A and the thermoplastic resin B) may be carried out before the kneading step or during the kneading step. EXAMPLES

[0055] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited thereto.

[0056] <Example 1> (Preparation of Thermoplastic Resin A) A mixture was obtained by mixing a base thermoplastic resin for thermoplastic resin A (100 parts by mass), a bisphenol compound (0.1 parts by mass), a radical initiator (0.775 parts by mass), and a compound having a functional group (1 part by mass) at 25°C.

[0057] Details of the materials used are as follows: Thermoplastic resin: Polypropylene (Sunallomer Co., Ltd., PLB00A, melt flow rate at 230°C and 2.16 kg load: 48 g / 10 min) Bisphenol compounds: Bisphenol A (Mitsubishi Chemical Corporation) Radical initiator: Dicumyl peroxide (NOF Corporation, Percumyl D-40) Compound with functional group: Polypropylene with maleic anhydride group (Kayabrid 006PP, Nouryon Chemical Co., Ltd.)

[0058] The obtained mixture was fed to a twin-screw extruder (Japan Steel Works, Ltd., TEX30α-42BW-3V) and melt-kneaded and extrusion-molded under the conditions of a cylinder temperature of 230°C, a screw rotation speed of 200 revolutions / minute (rpm), and a discharge rate of 10 kg / hr. The obtained molded product was cut into pellets of 3 mm length to obtain thermoplastic resin A in the form of pellets. The cylinder temperature was set so as to cause a reaction between the polypropylene and the polypropylene having a bisphenol compound and a maleic anhydride group, so that the thermoplastic resin A was in a state in which a bisphenol structure and a maleic anhydride group had been introduced into the polypropylene.

[0059] The resulting thermoplastic resin A had a weight average molecular weight of 160,000 and a melt flow rate of 100 g / 10 min at 180° C. under a load of 2.16 kg.

[0060] (Preparation of test specimens) The obtained thermoplastic resin A (10 parts by mass), thermoplastic resin B1 (90 parts by mass) as thermoplastic resin B, and glass fiber (30 parts by mass) were mixed, and a dumbbell-shaped test piece conforming to JIS K 7162 1A (1994) was produced using an injection molding machine (Toyo Machinery and Metals Co., Ltd., PLASTAR Si-130II) under the conditions shown in Table 1 below.

[0061] [Table 1]

[0062] <Examples 2 and 3> Test pieces were prepared in the same manner as in Example 1, except that the amounts of thermoplastic resin A and thermoplastic resin B1 were changed as shown in Table 2.

[0063] <Example 4> A test piece was prepared in the same manner as in Example 1, except that the thermoplastic resin B1 was changed to the thermoplastic resin B2.

[0064] <Examples 5 and 6> Test pieces were prepared in the same manner as in Example 4, except that the amounts of thermoplastic resin A and thermoplastic resin B2 were changed as shown in Table 2.

[0065] <Comparative Examples 1 and 2> Test pieces were prepared in the same manner as in Example 1, except that only the thermoplastic resin B1 or the thermoplastic resin B2 was used.

[0066] [Table 2]

[0067] Details of the materials used to prepare the test specimens are as follows: Thermoplastic resin B1: Polypropylene having a weight average molecular weight of 350,000 and a melt flow rate of 11 g / 10 min at 180° C. and a load of 2.16 kg. Thermoplastic resin B2: Polypropylene having a weight average molecular weight of 280,000 and a melt flow rate of 21 g / 10 min at 180° C. and a load of 2.16 kg. Glass fiber: chopped strands with a fiber length of 3 mm and a fiber diameter of 10 μm (Nippon Electric Glass Co., Ltd., T-480H)

[0068] (1) Dispersibility of glass fibers As an evaluation index for the dispersion of glass fibers in the test piece, the number of white spots originating from unspread glass fibers (areas surrounded by dotted lines) observed in the area surrounded by a frame as shown in Figure 1 of the test piece was investigated. The results are shown in Table 2.

[0069] (2) Bending strength The bending strength of the test pieces was measured by a method in accordance with JIS K 7171 (1994). The results are shown in Table 2.

[0070] As shown in Table 2, the test pieces of the examples containing thermoplastic resin A and thermoplastic resin B tended to have fewer white spots and greater bending strength than the test pieces of the comparative examples not containing thermoplastic resin A. From the above results, it was found that the use of thermoplastic resin A improves the dispersibility of glass fibers in the resin molding, and also improves the bending strength of the resin molding.

[0071] <Reference experiment> A resin molded body (resin molded body 1) having a shape of a back door inner was produced by injection molding using a mixture obtained by mixing the thermoplastic resin A obtained in the example with glass fiber. The spiral flow of the mixture at 230°C was 360 mm. Similarly, a resin molded body (resin molded body 2) in the shape of a back door inner was produced by injection molding using a commercially available mixture of glass fiber and polypropylene. The spiral flow of the mixture at 230°C was 240 mm.

[0072] Spiral flow was measured by injection molding a mixture obtained by mixing thermoplastic resin A with glass fiber, or a commercially available mixture of glass fiber and polypropylene, into a mold with a spiral groove under the conditions shown in Table 3 below using an injection molding machine (Toyo Machinery and Metals Co., Ltd., PLASTAR Si-130II), and measuring the flow distance (spiral flow length).

[0073] [Table 3]

[0074] The glass fiber content (mass %) was measured at 36 points for each of the produced resin molded bodies 1 and 2. The average, maximum and minimum values ​​of the measured values ​​are shown in Table 4.

[0075] [Table 4]

[0076] The glass fiber content of the resin molded body was measured by the following procedure. First, 36 test pieces were cut out from each of the resin molded body 1 and the resin molded body 2, and the cut test pieces were placed in a crucible and heated at 600°C for 3 hours using an electric furnace (Isuzu, VTDS-16). Next, after the electric furnace was cooled to room temperature, the crucible was removed from the electric furnace, and the glass fiber content was calculated from the mass of the incineration residue remaining in the crucible using the following formula 1. Glass fiber content (mass%) = incineration residue mass (g) / test piece mass before heat treatment (g) × 100 Formula 1

[0077] As shown in Table 4, resin molded body 1 made from a mixture obtained by mixing thermoplastic resin A and glass fiber showed a larger difference between the maximum and minimum glass fiber content and a tendency for the glass fiber content to vary more than resin molded body 2 made from a mixture of commercially available polypropylene and glass fiber. The reason for this is thought to be that the viscosity of thermoplastic resin A is too low, so the glass fibers separate from the resin during flow and are difficult to disperse uniformly.

[0078] From the above results, it is considered that, particularly when producing large resin molded products, appropriately adjusting the viscosity by using thermoplastic resin A and thermoplastic resin B in combination is effective in terms of suppressing uneven distribution of the reinforcing fibers.

Claims

1. A thermoplastic resin composition comprising a thermoplastic resin A having a bisphenol structure introduced therein and a thermoplastic resin B having no bisphenol structure introduced therein.

2. 2. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin A is polypropylene having a bisphenol structure introduced therein, and the thermoplastic resin B is polypropylene.

3. 3. The thermoplastic resin composition according to claim 1, wherein the weight average molecular weight of the thermoplastic resin A is smaller than the weight average molecular weight of the thermoplastic resin B.

4. The thermoplastic resin composition according to any one of claims 1 to 3, wherein the melt flow rate of the thermoplastic resin A at 180 ° C. and a load of 2.16 kg is greater than the melt flow rate of the thermoplastic resin B at 180 ° C. and a load of 2.16 kg.

5. A resin molded product comprising the thermoplastic resin composition according to any one of claims 1 to 4 and reinforcing fibers.

6. The resin molded article according to claim 5 , wherein the reinforcing fibers are glass fibers.

7. A method for producing a resin molded body, comprising: kneading the thermoplastic resin composition according to any one of claims 1 to 4 with reinforcing fibers to obtain a kneaded mixture; and molding the kneaded mixture.

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