Alloy resin and molded article

Abstract

To provide an alloy resin that contains fine cellulose fibers and exhibits a reduced degree of yellowing during molding, and a molded article produced using the alloy resin.SOLUTION: An alloy resin comprising a polycarbonate resin, fine cellulose fibers, and a polyvinyl chloride-based resin. It is preferable that 40 to 150 pts.mass of the polycarbonate resin is contained per 100 pts.mass of the polyvinyl chloride-based resin. The content of the fine cellulose fibers is preferably 10 to 40 mass% relative to the total mass of the alloy resin.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an alloy resin and a molded article. [Background technology]

[0002] In recent years, the use of plant-derived resin fillers has been required from the viewpoints of reducing environmental impact, carbon neutrality, etc. For example, Patent Document 1 discloses that by blending cellulose fibers into polycarbonate resin, it is possible to improve the physical properties of the resin, such as impact strength and rigidity (flexural modulus). Furthermore, the same document discloses that the problems of poor molded appearance (surface roughness) and reduced thermal stability (yellowing degree) caused by blending cellulose fibers are reduced by adding a terpene compound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 133228 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since terpene compounds are volatile, there are concerns that they will volatilize from molded articles and that this volatilization will cause quality deterioration. Therefore, the present inventors have investigated a method for solving the problem of yellowing caused by cellulose fibers added to resins without using terpene compounds, and have completed the present invention.

[0005] The present invention provides an alloy resin containing fine cellulose fibers and exhibiting reduced yellowing during molding, and a molded article using the alloy resin. [Means for solving the problem]

[0006] [1] An alloy resin comprising a polycarbonate resin, fine cellulose fibers, and a polyvinyl chloride resin. [2] The alloy resin according to [1], which contains 40 to 150 parts by mass of the polycarbonate resin per 100 parts by mass of the polyvinyl chloride resin. [3] The alloy resin according to [1] or [2], wherein the content of the fine cellulose fibers relative to the total mass of the alloy resin is 10 to 40 mass %. [4] The alloy resin according to any one of [1] to [3], wherein the melt flow rate of the polycarbonate resin measured in accordance with ISO 1133 at a temperature of 300°C and a load of 1.2 kg is 10 g / 10 min or more and 40 g / 10 min or less. [5] A molded article obtained by molding the alloy resin according to any one of [1] to [4]. [Effects of the Invention]

[0007] According to the present invention, the polycarbonate resin is blended with fine cellulose fibers and a vinyl chloride resin, thereby increasing the flexural modulus and reducing the degree of yellowing during molding. DETAILED DESCRIPTION OF THE INVENTION

[0008] <Alloy resin> A first aspect of the present invention is an alloy resin containing a polycarbonate resin (hereinafter referred to as "PC resin"), fine cellulose fibers, and a polyvinyl chloride resin (hereinafter referred to as "PVC resin").

[0009] [PC resin] The PC resin of this embodiment is not particularly limited, and examples thereof include aromatic polycarbonate resins and aliphatic polycarbonate resins, with aromatic polycarbonate resins being preferred. Specifically, an aromatic polycarbonate resin obtained by reacting an aromatic dihydroxy compound such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) with phosgene can be exemplified. The PC resin contained in the alloy resin may be one type or two or more types.

[0010] The MFR of the PC resin, measured according to ISO 1133 at a temperature of 300°C under a load of 1.2 kg, is preferably 10 g / 10 min or more, more preferably 15 g / 10 min or more, and even more preferably 25 g / 10 min or more. If the MFR of the PC resin is equal to or greater than the lower limit, the heat resistance temperature of the alloy resin is high and the strength of the molded product is high. The MFR of the PC resin is preferably 40 g / 10 min or less, more preferably 35 g / 10 min or less, and even more preferably 30 g / 10 min or less. If the MFR of the PC resin is equal to or less than the upper limit, the dispersibility in the alloy resin is good and the impact strength is high. The preferred lower and upper limits of the MFR (unit omitted) of the PC resin can be arbitrarily combined. For example, 10-40 is preferred, 15-35 is more preferred, and 25-30 is even more preferred.

[0011] The content of PC resin in the alloy resin is preferably 40 to 150 parts by mass per 100 parts by mass of PVC resin, and can be set within this range, for example, 50 to 120 parts by mass, 60 to 110 parts by mass, 70 to 100 parts by mass, or 80 to 90 parts by mass. Particularly within the range of 40 to 100 parts by mass, the flexural modulus tends to improve as the PC content increases.

[0012] The content of the PC resin relative to the total mass of the alloy resin can be, for example, 10 to 60 mass%, 20 to 50 mass%, or 30 to 40 mass%. In particular, within the range of 20 to 40 mass%, the flexural modulus tends to improve as the PC content increases.

[0013] [PVC resin] The PVC resin of this embodiment is a polymer in which the proportion of repeating units derived from vinyl chloride (hereinafter also referred to as "vinyl chloride units") exceeds 50 mass% based on the total mass of all repeating units. The PVC resin may be a homopolymer of vinyl chloride or a copolymer of vinyl chloride and a vinyl monomer copolymerizable with vinyl chloride. When the PVC-based resin is a copolymer, it may be a random copolymer, a block copolymer, or a graft copolymer. The PVC resin contained in the alloy resin may be one type or two or more types.

[0014] The proportion of vinyl chloride units in the PVC resin is preferably 75% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more, based on the total mass of all repeating units. The proportion of vinyl chloride units in the PVC resin may be 100% by mass.

[0015] The vinyl monomer copolymerizable with vinyl chloride is not particularly limited, and examples thereof include fatty acid vinyl esters, acrylates, methacrylates, vinyl cyanide, vinyl ethers, α-olefins, unsaturated carboxylic acids or their acid anhydrides, vinylidene chloride, vinyl bromide, and various urethanes. The vinyl monomer copolymerizable with vinyl chloride may be used alone or in combination of two or more.

[0016] Examples of fatty acid vinyl esters include vinyl acetate, vinyl propionate, and vinyl laurate. Examples of acrylates include methyl acrylate, ethyl acrylate, and butyl acrylate. Examples of methacrylate include methyl methacrylate and ethyl methacrylate. Examples of vinyl cyanide include acrylonitrile and methacrylonitrile. Examples of vinyl ethers include vinyl methyl ether, vinyl butyl ether, and vinyl octyl ether. Examples of the α-olefin include ethylene, propylene, and butylene. Examples of unsaturated carboxylic acids or acid anhydrides thereof include acrylic acid, methacrylic acid, and maleic anhydride.

[0017] The average degree of polymerization of the PVC resin is preferably at least 400, more preferably at least 500, and even more preferably at least 550. The average degree of polymerization of the PVC resin is preferably at most 1300, more preferably at most 800, and even more preferably at most 700. When the average degree of polymerization is within the range indicated by the above lower and upper limits, the dispersibility of the alloy resin and the processability of the molded article are further improved. The preferable lower and upper limits of the average polymerization degree of the PVC resin can be arbitrarily combined, and for example, 400 to 1,300 is preferable, 500 to 800 is more preferable, and 550 to 700 is even more preferable. The average degree of polymerization of the PVC resin is measured in accordance with JIS K 6720-2.

[0018] The PVC resin may be either a hard polyvinyl chloride resin or a soft polyvinyl chloride resin, but a hard polyvinyl chloride resin is preferred because it provides a molded product with high surface hardness and excellent scratch resistance.

[0019] The content of PVC resin relative to the total mass of the alloy resin can be, for example, 20 to 60 mass%, 30 to 55 mass%, or 35 to 50 mass%. In particular, within the range of 35 to 55 mass%, preferably 40 to 50 mass%, the flexural modulus tends to improve as the PVC content decreases.

[0020] [Fine cellulose fiber] The fine cellulose fibers of this embodiment refer to fiber materials consisting of an aggregate of cellulose molecules, including those commonly called cellulose nanofibers (nanocellulose), cellulose microfibrils, etc. The fine cellulose fibers contained in the alloy resin of this embodiment may be one type or two or more types.

[0021] Because microfibrillated cellulose fibers have a high aspect ratio, the fibers are entangled with each other, improving the mechanical properties of resins containing the fibers (fiber-reinforced resins). From this perspective, the following sizes are preferred: the fiber diameter is preferably 3 nm to 500 μm, more preferably 10 nm to 100 μm, and even more preferably about 100 nm to 10 μm; and the fiber length is preferably 0.1 to 1000 μm, and more preferably about 1 to 300 μm.

[0022] Some fine cellulose fibers turn into powder when dried, and are called powdered cellulose (cellulose powder). The apparent specific gravity of powdered cellulose is, for example, 0.2 to 0.5 g / cc. When powdered cellulose is observed under an electron microscope, the average particle size, calculated as the average of 100 fiber particles, is, for example, 20 to 100 μm.

[0023] Microcellulose fibers are generally obtained by defibrating plant materials such as pulp. Defibration methods include mechanical defibration using a defibrator such as a powerful shear mixer or ball mill grinder; chemical defibration using TEMPO catalytic oxidation; and defibration methods that combine these. Mechanical defibration generally tends to produce fibers with a large fiber diameter, while chemical defibration tends to produce fibers with a small diameter and short fiber length.

[0024] Known raw material cellulose for the fine cellulose fibers originates from plants (for example, wood, thinned wood, bamboo, hemp, jute, kenaf, agricultural and forestry waste, cloth, waste paper, pulp, etc.), algae, microorganisms, etc. Any of these may be used as the raw material for the fine cellulose fibers of this embodiment.

[0025] The content of the fine cellulose fibers in the alloy resin is preferably 10 to 100 parts by mass per 100 parts by mass of the PVC resin, and can be set within this range, for example, to 20 to 90 parts by mass, 30 to 80 parts by mass, 35 to 70 parts by mass, or 40 to 60 parts by mass.

[0026] The content of the fine cellulose fibers relative to the total mass of the alloy resin can be, for example, 10 to 60 mass%, 20 to 50 mass%, or 30 to 40 mass%. In particular, within the range of 20 to 30 mass%, preferably 20 to 25 mass%, the flexural modulus tends to improve as the content of the fine cellulose fibers decreases.

[0027] [Dispersant] The alloy resin of this embodiment preferably contains a dispersant for dispersing the fine cellulose fibers in the alloy resin. The dispersant may be a known surfactant or compatibilizer used for dispersing known fillers or reinforcing fibers in a resin. For example, a fatty acid ester surfactant is preferred.

[0028] The content of the dispersant in the alloy resin varies depending on the type of dispersant, but for example, in the case of a fatty acid ester surfactant, it is preferably 1.0 to 10 parts by mass per 100 parts by mass of the PVC resin, and can be, within this range, for example, 2.0 to 9.0 parts by mass, 3.0 to 8.0 parts by mass, 3.5 to 7.0 parts by mass, or 4.0 to 6.0 parts by mass.

[0029] The alloy resin of this embodiment may contain one or more additives such as heat stabilizers, light stabilizers, lubricants, antioxidants, modifiers, UV absorbers, plasticizers, antifouling agents, impact modifiers, colorants, and fillers, as needed, as long as the effects of the present invention are not impaired.

[0030] (Manufacturing method) The method for producing the alloy resin of the present invention is not particularly limited, and the alloy resin can be produced, for example, by kneading PC resin, fine cellulose fibers, PVC resin, and other components used as needed. Examples of the method for kneading the components of the alloy resin include kneading using a ribbon blender, a Henschel mixer, a Banbury mixer, a single-screw extruder, a twin-screw extruder, a co-kneader extruder, an injection molding machine, or the like, either alone or in combination.

[0031] The alloy resin of the present invention described above contains a PVC resin in addition to PC resin and fine cellulose fibers. Therefore, by using the alloy resin of the present invention, molded articles having a superior flexural modulus and reduced yellowing can be produced compared to conventional fiber-reinforced resins containing PC resin and fine cellulose fibers.

[0032] ≪Molded products≫ A second aspect of the present invention is a molded article obtained by molding the alloy resin of the first aspect. The molded article of this embodiment can be the same as a known molded article except that the alloy resin of the first embodiment is used. The use of the molded article of this embodiment is not particularly limited, and examples thereof include resin parts for automobiles, home appliances, etc.

[0033] The flexural modulus of the molded article of this embodiment is preferably 2900 MPa or more, more preferably 3400 MPa or more, and even more preferably 3900 MPa or more. There is no upper limit, but 5000 MPa is one guideline. Here, the flexural modulus is a value measured in accordance with the standard described below.

[0034] The method for producing the molded article of this embodiment is not particularly limited, and examples thereof include injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, and calendar molding.

[0035] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. [Example]

[0036] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following descriptions.

[0037] The details of the raw materials listed in Table 1 are as follows: The "vinyl chloride resin" is TK-700 manufactured by Shin-Etsu Chemical Co., Ltd., a PVC with a degree of polymerization of 700. The "dispersant" is Tirabazole D-818M manufactured by Taiyo Kagaku Co., Ltd., which is a fatty acid ester surfactant. The "polycarbonate resin" is SD Polyca 301-30, an aromatic polycarbonate resin manufactured by Sumika Polycarbonate Co., Ltd. Its MFR (ISO 1133 (JIS K 7210-1:2014), load 1.2 kg, temperature 300°C) is 30 g / 10 min. Its flexural modulus (ISO 178) is 2300 MPa. The "cellulose powder" is KC Flock W-100GK manufactured by Nippon Paper Industries Co., Ltd., which is a fine cellulose fiber with a 100 mesh pass rate of 90% or more, an apparent specific gravity of 0.30 to 0.40 g / cc, and an average particle size of 37 μm (reference value). The other raw materials in Table 1 are general-purpose materials used in general vinyl chloride resin compositions.

[0038] [Comparative Example 1] As shown in Table 1, a resin composition was prepared by mixing PC resin, cellulose powder, and a dispersant at a resin temperature of 230°C, and a plate-shaped molded product measuring 4 mm thick, 70 mm wide, and 150 mm long was produced by injection molding.

[0039] <Molding of alloy resin> [Examples 1 to 3, Comparative Example 2] As shown in Table 1, a material obtained by mixing PC resin, cellulose powder, a dispersant, and a vinyl chloride resin was kneaded at a resin temperature of 200°C to form an alloy resin, and a molded product was obtained in the same manner as in Comparative Example 1.

[0040] <Physical property evaluation> [Flexural modulus] The flexural modulus (unit: MPa) of the molded article of each example was measured in accordance with ISO 178 (i.e., JIS K7171:2016).

[0041] [Biomass ratio] The content (unit: %) of cellulose powder relative to the total mass of the mixed raw materials in each example was calculated.

[0042] [Heat resistance] The deflection temperature under load of each molded article was measured in accordance with Method A of JIS K7191-2:2015, and the deflection temperature under load was taken as the heat resistance temperature (°C).

[0043] [Pencil hardness] The pencil hardness of each molded article was measured in accordance with JIS K5600-5-4:1999.

[0044] [Yellowness] The YI value of each molded article was measured in transmission mode using a color difference meter (manufactured by Minolta Co., Ltd.) in accordance with JIS K7373: 2006. The larger the value, the more yellowing there is.

[0045] Table 1 shows the raw material blend amounts of the alloy resins in each example and the test results.

[0046] [Table 1]

[0047] The results of Comparative Example 1 show that blending fine cellulose fibers with PC resin can improve the flexural modulus of the PC resin from its original value of 2300 MPa to 2700 MPa. However, there is a problem in that the resin turns yellow during heat molding, resulting in a significantly increased yellowness. The results of Example 1 show that by blending fine cellulose fibers and PVC-based resin with PC resin to create an alloy resin, the flexural modulus can be significantly improved to 4000 MPa, and yellowing can be sufficiently reduced. Examples 2 and 3 are test examples in which the blending ratio of PC resin was reduced compared to Example 1, and the content of fine cellulose fiber relative to the total mass of the alloy resin was increased. The flexural modulus and yellowness index were slightly inferior to those of Example 1, but were significantly improved compared to Comparative Example 1. Comparative Example 2 is a test example in which the fine cellulose fibers were omitted from the formulation of Example 1. It can be seen that simply blending a PVC-based resin with a PC resin to form an alloy resin results in a lower flexural modulus than that of the original PC resin. From the above, it is clear that in the present invention, by using an alloy resin that is a blend of PC resin, fine cellulose fibers, and PVC-based resin, the flexural modulus is significantly improved compared to PC resin, and yellowing can be reduced.

Claims

1. An alloy resin comprising a polycarbonate resin, fine cellulose fibers, and a polyvinyl chloride resin.

2. 2. The alloy resin according to claim 1, wherein the polycarbonate resin is contained in an amount of 40 to 150 parts by mass per 100 parts by mass of the polyvinyl chloride resin.

3. The alloy resin according to claim 2, wherein the content of the fine cellulose fibers relative to the total mass of the alloy resin is 10 to 40 mass%.

4. 2. The alloy resin according to claim 1, wherein the melt flow rate of the polycarbonate resin measured in accordance with ISO 1133 at a temperature of 300°C under a load of 1.2 kg is 10 g / 10 min or more and 40 g / 10 min or less.

5. A molded article obtained by molding the alloy resin according to any one of claims 1 to 4.

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