Colored resin composition and molded article

Abstract

To provide a colored resin composition excellent in bleeding performance and mutual adhesion without impairing the hue of an organic pigment when a polyolefin resin is colored with an organic pigment and to provide a molded body obtained by forming the same which can suppress warpage and shrinkage.SOLUTION: There is provided a colored resin composition which comprises a polyolefin resin (A), an organic pigment (B) and a compatibilizer (C), wherein the compatibilizer (C) contains a polyolefin elastomer, ΔMDS represented by the following expression (1) satisfies 0.35% or less and ΔTDS represented by the following expression (2) satisfies 0.35% or less: Expression (1) ΔMDS=|X1-X0|, Expression (2) ΔTDS=|Y1-Y0|.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a colored resin composition and a molded article formed therefrom. [Background technology]

[0002] Plastics are easy to mold and process, and are used in a wide range of fields, including electrical and electronic equipment parts, automobile parts, medical parts, and food containers. Coloring of plastic molded products is becoming increasingly common to enhance their decorative appeal. In particular, in the beverage cap and container fields, there has been a trend toward multicoloring to differentiate products, and molded products with a variety of colors and designs are available on the market.

[0003] Among these, polyolefin resins are often used in the beverage cap and container fields due to their high resistance to the contents and ease of molding. However, when polyolefin resins are colored with pigments, the pigments can act as starting points for resin crystallization, and the resin crystallization can proceed along the crystalline direction of the pigment (hereinafter sometimes referred to as the nucleation effect). In this case, crystals that differ from the original crystalline structure of the resin are formed, resulting in dimensional problems such as warping and shrinkage in the resin molded product. Such warping and shrinkage of molded products are more likely to occur when organic pigments are used as colorants.

[0004] Known methods for suppressing warping and shrinkage of polyolefin resins caused by organic pigments include surface treatment of the pigment or addition of a derivative (Patent Documents 1 and 2), and modifying the composition of the polyolefin resin (Patent Document 3). However, these methods adversely affect the hue and bleeding properties of the pigment, surface peelability, and adhesion between resins. Furthermore, these methods have the problem of being usable only with polyolefin resins of limited compositions.

[0005] Also, a method of suppressing warpage and shrinkage by adding a nucleating agent to polyolefin resin is known (Patent Document 4). This method can suppress warpage and shrinkage when polyolefin resin is colored with an organic pigment, but in recent years, the market has been demanding more strict control of dimensional changes caused by coloring, and it has not been possible to achieve such high-precision dimensional stability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 4-226542 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-89612 [Patent Document 3] Patent No. 9-246718 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-225576 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention aims to provide a colored resin composition that, when a polyolefin resin is colored with an organic pigment, exhibits excellent bleeding properties, surface peeling properties, and mutual adhesion without impairing the hue of the organic pigment, and a molded article formed therefrom that exhibits reduced warping and shrinkage. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and as a result have completed the present invention. That is, the colored resin composition of the present invention is a colored resin composition containing a polyolefin resin (A), an organic pigment (B), and a compatibilizer (C), The compatibilizer (C) comprises a polyolefin elastomer; The present invention relates to a colored resin composition characterized in that ΔMDS represented by the following formula (1) is 0.35% or less, and ΔTDS represented by the following formula (2) is 0.35% or less. Equation (1) ΔMDS=|X1-X0| Equation (2) ΔTDS=|Y1-Y0| (Note that X1 and Y1 are the shrinkage rates in the same direction as the injection direction (MD) and the shrinkage rates in the direction perpendicular to the injection direction (TD), respectively, of a molded product of 150 mm in length, 120 mm in width, and 2 mm in thickness, which is molded from a colored resin composition using an injection molding machine, one day after molding. X0 and Y0 are the shrinkage percentages in the same direction as the injection direction (MD) and the direction perpendicular to the injection direction (TD), respectively, of a molded article of 150 mm length, 120 mm width, and 2 mm thickness, which is molded from polyolefin resin (A) using an injection molding machine, one day after molding. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a colored resin composition that exhibits excellent bleeding properties, surface peeling properties, and mutual adhesion properties without impairing the hue of the organic pigment when a polyolefin resin is colored with the organic pigment, and a molded article formed therefrom that is capable of suppressing warpage and shrinkage. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes in detail the embodiments of the present invention, but the following description is an example (typical example) of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not deviate from the gist of the present invention. Furthermore, in this specification, a numerical range specified using "to" is intended to include the numerical values before and after "to" as the range's lower and upper limits. Unless otherwise noted, the various components appearing in this specification may be used independently as a single type or as a mixture of two or more types. CI herein means Color Index.

[0011] 《Colored resin composition》 The colored resin composition of the present invention is used to form a molded article in which a polyolefin resin (A) is colored with an organic pigment. The colored resin composition contains the polyolefin resin (A), the organic pigment (B), and the compatibilizer (C), and the compatibilizer (C) contains a polyolefin elastomer. The glass is also characterized in that ΔMDS represented by the following formula (1) is 0.35% or less, and ΔTDS represented by the following formula (2) is 0.35% or less. Equation (1) ΔMDS=|X1-X0| Equation (2) ΔTDS=|Y1-Y0|

[0012] X1 is the shrinkage rate in the same direction as the injection direction (MD) of a molded body of 150 mm in length, 120 mm in width, and 2 mm in thickness, which is molded from a colored resin composition using an injection molding machine, one day after molding, and Y1 is the shrinkage rate in the direction perpendicular to the injection direction (TD).

[0013] X0 is the shrinkage percentage in the same direction as the injection direction (MD) of a molded article of polyolefin resin (A) molded using an injection molding machine, measuring 150 mm in length, 120 mm in width, and 2 mm in thickness, one day after molding, and Y0 is the shrinkage percentage in the direction perpendicular to the injection direction (TD).

[0014] When the polyolefin resin (A) is a mixture, X0 and Y0 can be determined using a molded product made only of the polyolefin resin (A) that contains the largest resin ratio in the polyolefin resin (A). When multiple resins contain the same ratio, the molded product made of the polyolefin resin (A) with the smallest shrinkage rate is used as the standard.

[0015] If ΔMDS and ΔTDS are 0.35% or less, it can be said that the molded article maintains dimensional stability with high precision, with dimensional changes caused by coloring with organic pigments being controlled. ΔMDS is more preferably 0.3% or less, further preferably 0.2% or less, and is preferably closer to 0%. Also, ΔTDS is more preferably 0.3% or less, preferably 0.2% or less, and is preferably closer to 0%. Within this range, it can be said that the molded article has a shrinkage difference controlled to the same level as that of a molded article made from an uncolored resin.

[0016] The colored resin composition can be obtained by kneading an organic pigment (B) and a compatibilizer (C) at a temperature at which the polyolefin resin (A) melts. For example, the colored resin composition can be produced by mixing or melt-kneading the polyolefin resin (A), the organic pigment (B), the compatibilizer (C), and, if necessary, various additives, using a kneader, roll mill, super mixer, high-speed mixer, ball mill, sand mill, attritor, or batch mixer such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, or a rotor-type twin-screw kneader to produce a resin composition in the form of pellets, powder, granules, or beads. Because of their strong kneading power and ease of subsequent molding, pelletization using a single-screw or twin-screw extruder is preferred.

[0017] The colored resin composition may be prepared by blending the polyolefin resin (A) with the organic pigment (B) and the compatibilizer (C) in the required amounts and then molding the mixture as is. Alternatively, a masterbatch containing the organic pigment (B) at a high concentration may be prepared, and the masterbatch may be diluted with a diluting resin before being used for molding.

[0018] <Polyolefin resin (A)> The polyolefin resin (A) in the present invention is a polymer of an olefin monomer such as ethylene, propylene, or butylene, and may be a block or random copolymer having a melting point in the range of 40 to 200° C., or may be a bipolymer or terpolymer, etc. Specific examples include polymers of α-olefins such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), high-density polyethylene resin (HDPE), and polypropylene resin (PP). The polyolefin resin (A) is preferably HDPE or PP, which has high crystallinity, as this makes it easier to obtain the effects of the present invention. The melting points in this specification are values measured using a differential scanning calorimeter "DSC6200" (Seiko Instruments Inc.) under conditions of a temperature range of 40 to 200°C and a temperature rise rate of 10°C / min.

[0019] When a masterbatch is prepared, the MFR (melt flow rate, also referred to as melt viscosity) of the polyolefin resin (A) is preferably 5 to 100 g / 10 min, more preferably 10 to 60 g / 10 min. If the MFR of the polyolefin resin (A) is 5 g / 10 min or more, the masterbatch is sufficiently distributed when added to the diluent resin, thereby further preventing the occurrence of poor appearance such as color unevenness in the molded article. On the other hand, if the MFR is 100 g / 10 min or less, it is possible to prevent a decrease in the melt viscosity of the entire system during molding, which would affect moldability. The polyolefin resin (A) and diluent resin used in the masterbatch are preferably the same type of polyolefin resin. For example, if the diluent resin polyolefin resin (A) is HDPE, the polyolefin resin (A) in the masterbatch is also preferably HDPE.

[0020] When the polyolefin resin (A) of the colored resin composition is a high-density polyethylene resin (HDPE) or a polypropylene resin (PP), the MFR of the polyolefin resin (A) is preferably 5 g / 10 min or less, more preferably 0.1 to 5 g / 10 min. If the MFR of the polyolefin resin (A) is 0.1 g / 10 min or more, the processability of the colored resin composition will be improved, and if it is 5 g / 10 min or less, the strength of the molded article will be improved. The MFR in the present invention is a value measured in accordance with JIS (Japanese Industrial Standards) K-7210.

[0021] Specific examples of the polyolefin resin (A) include Novatec LL UJ580 (LLDPE, MFR: 20 g / 10 min, manufactured by Japan Polyethylene Co., Ltd.), Suntec LD M2270 (LDPE, MFR: 7 g / 10 min, manufactured by Asahi Kasei Corporation), Suntec HD J240 (HDPE, MFR: 5 g / 10 min, manufactured by Asahi Kasei Corporation), Suntec HD J300 (HDPE, MFR: 42 g / 10 min), and Prime Polypro J229E (PP, MFR: 50 g / 10 min, manufactured by Prime Polymer Co., Ltd.).

[0022] The content of the polyolefin resin (A) in 100% by mass of the resin composition is preferably 60% by mass or more and 100% by mass or less, and more preferably 90% by mass or more. If the content of the polyolefin resin (A) is 60% by mass or more, it is easy to maintain sufficient strength of the molded product.

[0023] <Organic pigment (B)> The organic pigment (B) in the present invention is not particularly limited as long as it is a pigment made of an organic substance. Examples of suitable pigments include azo pigments, quinacridone pigments, perylene pigments, isoindolinone pigments, diketopyrrolopyrrole pigments, and phthalocyanine pigments. Among these, azo pigments, quinacridone pigments, perylene pigments, isoindolinone pigments, and diketopyrrolopyrrole pigments are preferred in terms of their high compatibility with the compatibilizer (C) and shrinkage rate. More preferred are diketopyrrolopyrrole pigments, which have good dispersibility as pigments and are therefore preferred in terms of their excellent hue.

[0024] Specific examples of azo pigments include CI Pigment Yellow 93, 95, 150, 151, 168, 169, 180, and 181, and CI Pigment Red 144, 208, and 214. Specific examples of quinacridone pigments include CI Pigment Red 122, 207, CI Pigment Violet 19, Specific examples of perylene pigments include CI Pigment Red 149, 178, Specific examples of isoindolinone pigments include CI Pigment Yellow 109, 110, 139, CI Pigment Orange 61, Specific examples of diketopyrrolopyrrolopyrrole pigments are CI Pigment Red 254, 264, and CI Pigment Orange 71. etc.

[0025] A specific example of Pigment Yellow 93 is Cromophtal Yellow 3GNP (manufactured by BASF), a specific example of Pigment Yellow 95 is Cromophtal Yellow GRP (manufactured by BASF), a specific example of Pigment Yellow 150 is Bainamon Yellow 115002 (manufactured by Heubach), a specific example of Pigment Yellow 151 is PV Fast Yellow H4G (manufactured by Clariant), and a specific example of Pigment Yellow 168 is Lionol Yellow K5G (manufactured by Toray). A specific example of Pigment Yellow 169 is Lionol Yellow K2R (manufactured by Toyocolor Co., Ltd.), a specific example of Pigment Yellow 180 is PV Fast Yellow HG (manufactured by Clariant), a specific example of Pigment Yellow 181 is PV Fast Yellow H3R (manufactured by Clariant), a specific example of Pigment Red 144 is Cromophtal Red BRN (manufactured by BASF), a specific example of Pigment Red 208 is Grafthol Red HF2B (manufactured by BASF), a specific example of Pigment Red 214 is Chromophthal Red BN (manufactured by BASF), a specific example of Pigment Red 122 is Fastgen Super Magenta RE03 (manufactured by DIC), Binamon Red 312201 (manufactured by Heuba), a specific example of Pigment Red 207 is Fastgen Super Scarlet GK (manufactured by DIC), a specific example of Pigment Bio Red 19 is Chromophthal Red 2020 (manufactured by BASF), Pigment A specific example of Red 149 is Paliogen Red K3580 (manufactured by BASF), a specific example of Pigment Red 178 is Paliogen Red K3911HD (manufactured by BASF), a specific example of Pigment Red 254 is Chromophtal Red 2028 (manufactured by BASF), a specific example of Pigment Red 264 is Irgazin DPP Rubin TR (manufactured by BASF), and a specific example of Pigment Orange 71 is Chromophtal DPP Orange TRP (manufactured by BASF).

[0026] The organic pigment (B) preferably has a structure having a polar functional group, because the polar functional group provides high compatibility with the compatibilizer (C). Specific examples of pigments having a polar functional group include CI Pigment Yellow 93, 95, 110, 150, and 151, CI Pigment Red 122, 149, 207, and 254, and CI Pigment Violet 19.

[0027] The content of the organic pigment (B) is preferably 0.01% by mass or more, more preferably 0.1% by mass or more and 1% by mass or less, and even more preferably 0.3% by mass or more and less than 0.8% by mass, based on 100% by mass of the colored resin composition. When the content of the organic pigment (B) is within the above range, it becomes easier to achieve both the dispersibility of the organic pigment (B) and the processability of the resin composition.

[0028] <Compatibilizer (C)> The compatibilizer (C) in the present invention contains a polyolefin elastomer. This makes it possible to suppress warping and shrinkage of a molded article made from the organic pigment (B) and the polyolefin resin (A). It is believed that the interaction between the polyolefin elastomer and the organic pigment (B) weakens the nucleating effect of the organic pigment (B), thereby suppressing warping and shrinkage of the polyolefin resin (A). Furthermore, by using a polyolefin elastomer, the organic pigment (B) can be stably dispersed without being affected by the hue change caused by the compatibilizer, and it is possible to form a molded product with suppressed hue change. Other compatibilizers may also be used in combination.

[0029] The polyolefin elastomer is preferably a polymer having an olefin moiety that does not exhibit a melting point in the range of 40 to 200°C. The melting points in this specification are values measured using a differential scanning calorimeter "DSC6200" (Seiko Instruments Inc.) under conditions of a temperature range of 40 to 200°C and a temperature rise rate of 10°C / min.

[0030] Examples of the olefin moiety of the polyolefin elastomer include α-olefins such as ethylene, propylene, and diene. Specific examples of the polyolefin elastomer include α-olefin copolymers and styrene-olefin copolymers. The MFR of the compatibilizer (C) is preferably 1 to 10 g / 10 min, more preferably 1 to 5 g / 10 min. An MFR in the above range is preferred because it provides better compatibility with the polyolefin resin (A).

[0031] The α-olefin copolymer is produced by polymerizing α-olefins using a catalyst comprising, for example, a transition metal compound and an organoaluminum compound, a so-called Ziegler catalyst.

[0032] Specific examples of α-olefins include propylene, 1-butene, 2-methyl-1-propene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, and dimethyl-1-pentene. Examples of the olefin include 1-octene, 1-pentene, ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, 1-octene, methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene, propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, 1-nonene, 1-decene, 1-undecene, and 1-dodecene. Of these, α-olefins having 3 to 10 carbon atoms are preferred, and α-olefins having 3 to 8 carbon atoms are more preferred. The closer the olefin content is to the above range, the better the compatibility with the polyolefin resin (A).

[0033] The styrene-olefin copolymer is a copolymer having units derived from an olefin and units derived from styrene, and can be produced, for example, by polymerization in the presence of a metal catalyst such as a Ziegler-Natta catalyst.

[0034] Specific examples of the olefin moiety of the styrene-olefin copolymer include monoolefins such as α-olefins such as ethylene, propylene, and butene, and diolefins (conjugated dienes) such as butadiene and isoprene.

[0035] Specific examples of the styrene moiety of the styrene-olefin copolymer include styrene, α-methylstyrene, and p-methylstyrene.

[0036] The proportion of olefin moieties in the polyolefin elastomer is preferably 50% by mass or more, more preferably 70% by mass or more and 100% by mass or less, based on 100% by mass of the polyolefin elastomer. If the proportion of olefin is 50% by mass or more, the proportion of styrene is not too high, which increases compatibility with the polyolefin resin (A) and makes it easier to prevent poor appearance such as surface peeling of the molded article. When the proportion of polyolefin is 100% by mass, a single component is preferred over a mixture because it has good compatibility with the resin.

[0037] The polyolefin elastomer preferably has an acidic functional group, which enhances the interaction with the organic pigment (B). Examples of the acidic functional group include a carboxyl group (-COOH) and a carboxylic anhydride group (O=COC=O).

[0038] The acid value of the polyolefin elastomer having an acidic functional group is preferably 1 to 30 mgKOH / g, more preferably 5 to 26 mgKOH / g. When the acid value of the polyolefin elastomer is within the above range, the compatibility between the polyolefin elastomer and the organic pigment (B) can be improved. The acid value in the present invention is a value measured in accordance with JIS K-0070.

[0039] The blending ratio of the compatibilizer (C) to the organic pigment (B) [(C) / (B)] is preferably 0.05 to 1, and more preferably 0.1 to 0.8. When the blending ratio is 0.05 or more, warping and shrinkage can be suppressed effectively, and when it is 1 or less, adhesion of the colored resin composition to each other can be further suppressed, facilitating stable supply. Preferably, the blending ratio of the polyolefin elastomer to the organic pigment (B) [polyolefin elastomer / (B)] is 0.05 to 1. More preferably, it is 0.05 to 0.8, and even more preferably, it is 0.1 to 0.8.

[0040] When the organic pigment (B) is a diketopyrrolopyrrole pigment, the polyolefin elastomer is preferably an acid-modified styrene-diene copolymer, and the above combination is most effective in preventing warpage and shrinkage due to crystallization.

[0041] Specific examples of polyolefin elastomers include Tufmer A4085S (manufactured by Mitsui Chemicals, Inc., ethylene-α-olefin copolymer), Excellen FX FX558 (manufactured by Sumitomo Chemical Co., Ltd., ethylene-1-hexene copolymer), Tuftec H1052 (manufactured by Asahi Kasei Corporation, styrene-butadiene copolymer, styrene compound unit content 30% by mass), Tuftec M1911 (manufactured by Asahi Kasei Corporation, acid value: 2 mg KOH / g, maleic anhydride-modified styrene-diene copolymer, styrene compound unit content 20% by mass), and Tuftec M1943 (manufactured by Asahi Kasei Corporation, acid value: 10 mg KOH / g, maleic anhydride-modified styrene-diene copolymer, styrene compound unit content 20% by mass).

[0042] <Optional ingredients> The colored resin composition of the present invention may contain additives such as metal soaps of alkali metals, alkaline earth metals, or zinc, hydrotalcite, nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, antistatic agents, flame retardants such as halogen-based, phosphorus-based, or metal oxides, antioxidants, ultraviolet absorbers, fillers, and inorganic pigments according to desired hues, within the range that does not impair the effects of the present invention.

[0043] Examples of the inorganic pigment include titanium oxide, calcium carbonate, barium sulfate, zinc sulfide, iron oxide, ultramarine, cobalt blue, nickel titanium yellow, bismuth yellow, carbon black, and pearl pigments.

[0044] <<Molded body>> The molded article is molded using the colored resin composition of the present invention. The molding method is not particularly limited, and the composition can be obtained by extrusion molding, compression molding, injection molding, blow molding, or the like. The molded article may be formed directly from a colored resin composition obtained by kneading an organic pigment (B) and a compatibilizer (C) at a temperature at which the polyolefin resin (A) melts, or may be formed from a colored resin composition obtained by forming a masterbatch containing a high concentration of the organic pigment (B) and then kneading it with a polyolefin resin, which is a diluted resin, at a specified ratio when molding the molded article. The diluting resin in this case may be the same resin as the polyolefin resin (A) constituting the masterbatch or a different resin, but is preferably the same resin.

[0045] The content of the polyolefin resin (A) in 100% by mass of the masterbatch is preferably 20% by mass or more, and more preferably 30 to 60% by mass. When the blending amount of the polyolefin resin (A) is 20% by mass or more, the processability during the production of the masterbatch becomes better. The content of the organic pigment (B) in 100% by mass of the masterbatch is preferably from 1 to 60% by mass, more preferably from 5 to 50% by mass, in 100% by mass of the colored resin composition.

[0046] The content of the polyolefin resin (A) in 100% by mass of the molded article is preferably 60% by mass or more and 100% by mass or less, and more preferably 90% by mass or more. When the blending amount of the polyolefin resin (A) is 60% by mass or more, it is easy to maintain sufficient strength of the molded article. The content of the organic pigment (B) in 100% by mass of the molded body is preferably 0.01% by mass or more, more preferably 0.1% by mass or more and 1% by mass or less, and even more preferably 0.3% by mass or more and less than 0.8% by mass, in 100% by mass of the colored resin composition.

[0047] The molded article formed from the colored resin composition of the present invention is excellent in suppressing warping and shrinkage, and therefore can be suitably used for beverage caps molded by compression molding or injection molding, as well as containers molded by blow molding (direct blow, injection blow). Among these, injection molding is preferred because it can suppress shrinkage of the molded body, control dimensional changes due to coloring, and produce a molded body that maintains dimensional stability with high precision. [Example]

[0048] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified. The blend amounts in the table are in parts by mass, and blank spaces indicate that no blend was used. The melt viscosity of the polyolefin resin (A) and the acid value of the compatibilizer (C) are measured by the following methods.

[0049] [Melt viscosity of polyolefin resin (A)] The MFR was measured according to JIS (Japanese Industrial Standards) K-7210. [Acid value of compatibilizer (C)] The acid value was measured in accordance with JIS K-0070.

[0050] The materials used in the examples and comparative examples are listed below. <Polyolefin resin (A)> A-1: Hi-Zex 2208J (Prime Polymer, MFR: 5g / 10min, HDPE) A-2: Prime Polypro J105G (Prime Polymer Co., Ltd., MFR: 9g / 10min, PP) A-3: Suntec HD J300 (Asahi Kasei Corporation, MFR: 42g / 10min, HDPE) <Organic pigment (B)> B-1: Irgazin Yellow 3RLT-N (BASF, PY110, Isoindolinone Yellow) B-2: Binamon Red 325401 (Heubach, PR254, Diketopyrrolopyrrole Red) B-3: Paliogen Red K3911HD (BASF, PR178, Perylene Red) B-4: Lionol Blue FG7330 (Toyo Color Co., Ltd., PB15.3, β-phthalocyanine blue) <Compatibilizer (C)> [Polyolefin elastomer] C-1: Tafmer A4085S (Mitsui Chemicals, melting point: 66°C, ethylene-α-olefin copolymer, olefin moiety 100% by mass) C-2: Tuftec H1043 (manufactured by Asahi Kasei Corporation, styrene-diene copolymer, styrene compound unit content 67% by mass, olefin moiety 33% by mass) C-3: Tuftec M1943 (manufactured by Asahi Kasei Corporation, acid value: 10 mg KOH / g, maleic anhydride-modified styrene-diene copolymer, styrene compound unit content: 20% by mass, olefin moiety: 80% by mass) [Other compatibilizers] CC-1: Hiwax NP50605A (Mitsui Chemicals, Inc., acid value: 61, melting point: 143°C, maleic anhydride-modified polyolefin wax)

[0051] Example 1 99.45 parts of polyolefin resin (A-1), 0.5 parts of organic pigment (B-1), and 0.05 parts of compatibilizer (C-1) were mixed, extruded at 200°C using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.), and granulated to obtain a pellet-shaped colored resin composition (D-1). Next, 100 parts of the obtained colored resin composition (D-1) was used to mold using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) under the injection conditions described below, and the molded product was stored for one day in a constant temperature room at 23°C and 50% RH to obtain a plate-shaped molded body 1.

[0052] <Examples 2 to 11 and Comparative Examples 1 to 4> The same as in Example 1 except that the materials and blending amounts (parts by mass) were changed to those shown in Tables 1 and 2. By this method, pellet-shaped colored resin compositions (D-2 to 11, 14 to 17) were obtained, respectively. Subsequently, 100 parts of the obtained colored resin composition was used to inject a resin into an injection molding machine ( Toshiba Machine Co., Ltd.) and store in a constant temperature room at 23°C and 50% RH for one day to form into a plate. Bodies 2 to 11 were obtained. However, in the example 1, 3, and 4 is a reference example.

[0053] Example 12 77.4 parts of polyolefin resin (A-3), 20 parts of organic pigment (B-2), and 2.6 parts of compatibilizer (C-3) were mixed, extruded at 200°C using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.), and granulated to obtain a pellet-shaped masterbatch (MB-1). Next, 4 parts of the obtained masterbatch (MB-1) and 100 parts of polyolefin resin (A-1) were mixed to obtain a colored resin composition (D-12), which was then molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) under the injection conditions described below.The resulting mixture was then stored for one day in a constant temperature room at 23°C and 50% RH to obtain a plate-shaped molded body 12.

[0054] Example 13 54.9 parts of polyolefin resin (A-3), 40 parts of organic pigment (B-2), and 5.1 parts of compatibilizer (C-3) were mixed, extruded at 200°C using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd.), and granulated to obtain a pellet-shaped masterbatch (MB-2). Next, 2 parts of the obtained masterbatch (MB-2) and 100 parts of polyolefin resin (A-1) were mixed to obtain a colored resin composition (D-13), which was then molded using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) under the injection conditions described below.The resulting mixture was then stored for one day in a constant temperature room at 23°C and 50% RH to obtain a plate-shaped molded body 12.

[0055] [Manufacturing conditions for molded body (plate-shaped molded body)] The manufacturing conditions for the molded bodies (plate-shaped molded bodies) were as follows: 20 pieces were injection-molded consecutively using an injection molding machine (manufactured by Toshiba Machine Co., Ltd.) at a molding temperature of 220°C and a mold temperature of 40°C. Of these, six pieces, from the 14th to the 19th, were used for evaluation after being stored in a thermostatic chamber at 23°C and 50 RH for one day. As an evaluation standard, a molded plate (sometimes referred to as "natural") molded under the same conditions using only the polyolefin resin (A) was used. The mold used to produce the plate-shaped molded product was a mold capable of producing a plate 150 mm long, 120 mm wide and 2 mm thick, with 100 mm markings in the injection direction and in the direction perpendicular to it.

[0056] <Measurement of shrinkage rate> Using six of the obtained molded plates, the distance between the gauge lines was measured with a precision caliper, and the average shrinkage rate in the injection direction and the direction perpendicular to it was calculated from this value. The shrinkage difference rate was calculated using the following formula:

[0057] The values of X0 and Y0 in the resin compositions of Examples 12 and 13 were determined using polyolefin resin (A-1), which is the main component of polyolefin resin (A).

[0058] Equation (1)ΔMDS=|X1-X0| Equation (2)ΔTDS=|Y1-Y0| (Note that X1 and Y1 are the shrinkage rates in the same direction as the injection direction (MD) and the shrinkage rates in the direction perpendicular to the injection direction (TD), respectively, of a molded product having a length of 150 mm, a width of 120 mm and a thickness of 2 mm, which is molded from a colored resin composition using an injection molding machine, one day after molding.) X0 and Y0 are the shrinkage percentages in the same direction as the injection direction (MD) and the direction perpendicular to the injection direction (TD), respectively, of a molded article of 150 mm length, 120 mm width, and 2 mm thickness molded from polyolefin resin (A) using an injection molding machine, one day after molding.

[0059] That is, for example, in Example 1, a molded article having a length of 150 mm, a width of 120 mm and a thickness of 2 mm, which is molded from Resin Composition 1 using an injection molding machine, has a shrinkage ratio in the same direction as the injection direction (MD) one day after molding of X1 and a shrinkage ratio in the direction perpendicular to the injection direction (TD) of X2, and a molded article having a length of 150 mm, a width of 120 mm and a thickness of 2 mm, which is molded from Polyolefin Resin (A-1) using an injection molding machine, has a shrinkage ratio in the same direction as the injection direction (MD) one day after molding of X0 and a shrinkage ratio in the direction perpendicular to the injection direction (TD) of Y0.

[0060] X1: Shrinkage rate of molding plate 1 in the injection direction =molding One day later Rear MD direction gauge distance mm / 100mm x 100 Y1: Shrinkage rate of molding plate 1 in the direction perpendicular to the injection direction =molding One day later Rear TD direction gauge distance mm / 100mm x 100 X0: Shrinkage rate in the injection direction for natural resin using only polyolefin resin (A-1) =Natural molding One day later Rear MD direction gauge distance mm / 100mm x 100 Y0: Orthogonal to the injection direction of natural resin (A-1) Shrinkage rate in the direction =Natural molding One day later Rear TD direction gauge distance mm / 100mm x 100

[0061] (Evaluation of Resin Composition) <Bleeding evaluation> 100 g of the colored resin composition was left to stand at 60° C. for 2 days, and the state of the pellet surface was evaluated visually. If no bleeding substance was observed on the pellet surface, it was marked "○", and if bleeding substance was clearly observed, it was marked "×".

[0062] <Interadhesion evaluation> The resin composition was placed in a Menthol can with a diameter of 5 cm and a depth of 3 cm, and then heated in an oven at 60°C for one day with a 1 kg weight placed on top. After that, it was allowed to cool to room temperature, the Menthol can was removed, and the degree of adhesion of the pellets to each other was evaluated. If no pellets were found to be sticking together, it was marked "Good", if a small amount of pellets were found to be sticking together, it was marked "Good", and if more than half of the pellets were found to be sticking together, it was marked "Poor". If the rating was "Good" or better, it could be used for feeding pellets without any problems.

[0063] (Evaluation of molded body) <Warping> A 2 kg weight was placed on the gate of the obtained molded product, and the height of the lift from the horizontal position was measured. If there was no lift, it was marked "○", if the height was 2 mm or less, it was marked "△", and if the height was more than 2 mm, it was marked "×". If it was marked "△" or better, it was usable.

[0064] <Hue> Using a Kurabo AU Color COLOR7x image spectrophotometer, the L of the molded body was measured using a D-65(10) standard light source. * , a * , b * The values were measured (L * 1, a * 1, b * (Let's say it's 1). In addition, as a control, a resin composition containing the same kind of pigment as the molded body at the same concentration, but not containing the compatibilizer (C), was used to produce a control molded body under the same conditions. * , a * , b * The values were measured (L * 0, a * 0, b * 0). Hue evaluation is calculated by the color difference (△E *) was calculated. △E * If it was 0.5 or less, it was marked as "◎", if it was more than 0.5 and less than 1, it was marked as "○", and if it was 1 or more, it was marked as "×". △E * The smaller the value, the less the hue change caused by the compatibilizer and the more stably the organic pigment (B) is dispersed. A value of ◯ or more is practically usable. Formula (3) △E * =[(L * 1-L * 0) 2 +(a * 1-a * 0) 2 +(b * 1-b * 0) 2 ] 1 / 2

[0065] <Surface peeling> Using the obtained molded articles, cellophane tape was stuck and peeled off in one go in four places on each of six molded articles to check for peeling. The total number of peeled places was added up, and if peeling occurred in a total of five places or less, the surface peelability was deemed good and rated as "○", if peeling occurred in six or more but less than ten places, it was rated as "△", and if peeling occurred in ten places or more, it was deemed poor and rated as "×". If it was △ or better, it was usable.

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] [Table 4]

[0070] As shown in Tables 3 and 4, a colored resin composition (D) containing a polyolefin resin (A), an organic pigment (B), and a compatibilizer (C), wherein the compatibilizer (C) is a polyolefin elastomer, and further, the ΔMDS represented by formula (1) is 0.35% or less, and the ΔTDS represented by formula (2) is 0.35% or less. It was confirmed that a molded article with suppressed warpage and shrinkage can be obtained without impairing the hue, bleeding properties, surface peeling properties, and mutual adhesion of the pigment.

Claims

1. A colored resin composition containing a polyolefin resin (A), an organic pigment (B), and a compatibilizer (C), The organic pigment (B) includes a diketopyrrolopyrrole pigment, the compatibilizer (C) contains at least one of an α-olefin copolymer and a styrene-olefin copolymer; The content of the organic pigment (B) is 0.25% by mass or more and 1% by mass or less in 100% by mass of the colored resin composition, the compounding ratio of the organic pigment (B) to the compatibilizer (C) [(C) / (B)] is 0.05 to 1; A colored resin composition characterized in that ΔMDS represented by the following formula (1) is 0.35% or less, and ΔTDS represented by the following formula (2) is 0.35% or less. Formula (1) ΔMDS=|X1-X0| Formula (2) ΔTDS=|Y1-Y0| (Note that X1 and Y1 are the shrinkage rates in the same direction as the injection direction (MD direction) and the shrinkage rates in the direction perpendicular to the injection direction (TD direction), respectively, of a molded article having a length of 150 mm, a width of 120 mm, and a thickness of 2 mm, which is molded from a colored resin composition using an injection molding machine, one day after molding.) X0 and Y0 are the shrinkage percentages in the same direction as the injection direction (MD) and the direction perpendicular to the injection direction (TD), respectively, of a molded article having a length of 150 mm, a width of 120 mm and a thickness of 2 mm, which is molded from polyolefin resin (A) using an injection molding machine, one day after molding.

2. 2. The colored resin composition according to claim 1, wherein the styrene-olefin copolymer has an olefin moiety ratio of 50% by mass or more.

3. 3. The colored resin composition according to claim 1, wherein the compatibilizer (C) comprises a styrene-olefin copolymer having an acidic functional group.

4. A molded article formed from the colored resin composition according to any one of claims 1 to 3.

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