JP2008231354A - Resin composition and injection-molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection-molded article superior in heat resistance and impact resistance, and a resin composition for molding the injection-molded article, which can be converted into an article having a thin wall. <P>SOLUTION: The injection-molded article is formed by using the resin composition formed by blending a lactic resin (A), an aromatic polycarbonate-based resin (B) having a melt flow rate measured according to JIS K7210 of 60-90 g/10 min under the condition of 300°C and 1.2 kg load, a non-styrenic rubber or elastomer (C), and a crystalization promotor (D), in a specified ratio, wherein the ratio of component (B) in the mixture of the lactic resin (A) and the aromatic polycarbonate-based resin (B) is 20 mass% or higher and lower than 45 mass%, and 1-10 pts.mass of the component (C), and 0.1-5 pts.mass of the component (D) are blended into 100 pts.mass of the sum of the masses of the component (A) and the component (B). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition and an injection-molded body, and particularly to a resin composition and an injection-molded body having heat resistance, impact resistance, and fluidity.

  Polycarbonate resins are excellent in heat resistance and impact resistance, and are therefore used in various applications as injection molded products for home appliances, OA equipment, automobile parts and the like. However, since the polycarbonate-based resin is inferior in fluidity, it has been very difficult to use it for thin-wall molding or the like that particularly requires high fluidity.

  For this reason, conventionally, polycarbonate has been blended with acrylonitrile / butadiene / styrene copolymer (ABS resin) to improve fluidity. However, when an ABS resin is blended with a polycarbonate resin, the heat resistance inherent in the polycarbonate resin is impaired, so there is a limit to the improvement in fluidity.

  As another method for improving the fluidity of a polycarbonate resin, a method of blending a lactic acid resin has recently been studied. For example, as a technique related to the blending of a polycarbonate resin and a lactic acid resin, a blend of a resin composition comprising an aromatic polycarbonate resin and polylactic acid (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3), Alternatively, a blend of polylactic acid and an amorphous resin (for example, polycarbonate resin) having a glass transition temperature higher than that of polylactic acid (for example, see Patent Document 4) is known. By simply blending a polycarbonate resin and polylactic acid, fluidity is hardly improved. On the contrary, blending polylactic acid significantly lowers impact resistance.

  Alternatively, a method in which an aromatic polycarbonate and an aliphatic polyester such as a lactic acid resin are heated and dehydrated in the presence of a catalyst (see, for example, Patent Document 5), a polyisocyanate compound added to an amorphous resin such as polylactic acid and a polycarbonate A resin composition (for example, see Patent Document 6), a resin composition (for example, see Patent Document 7) in which a radical reaction initiator is blended with polylactic acid and polycarbonate are known. The technology does not improve the flowability of polycarbonate. Moreover, since the impact resistance is reduced, it is difficult to say that this is a practical technique.

  Alternatively, a resin composition comprising an aromatic polycarbonate, polylactic acid, and an inorganic filler (for example, see Patent Document 8), a resin composition comprising an aromatic polycarbonate, polylactic acid, and an impact modifier (for example, a patent) However, the former has almost no effect of improving fluidity due to the presence of aromatic polycarbonate as a matrix, and the latter can be obtained by blending polylactic acid by blending an impact modifier. Although the reduced impact resistance can be improved, the flowability is not improved because the aromatic polycarbonate exists as a matrix.

  Alternatively, a resin composition comprising a resin mixture comprising 45 to 97% by mass of a polycarbonate and 55 to 3% by mass of a fatty acid polyester such as polylactic acid and a rubber-like elastic body (for example, Patent Document 10 and Patent Document 11). However, even when the polycarbonate is blended in an amount of 45% by mass or more, the fluidity as the resin composition is dominated by the polycarbonate, and sufficient fluidity cannot be ensured. . Furthermore, when styrene rubber or elastomer is blended with polycarbonate, crystallization of lactic acid resin is inhibited, and in particular, when the ratio of lactic acid resin is 50% by mass or more, cycle extension during crystallization treatment is prolonged. Such problems occur.

Japanese Patent Application Laid-Open No. 07-109413 JP-A-11-140292 JP 2004-250549 A JP 2005-60637 A JP 09-216942 A JP 2000-017038 A JP 2002-371172 A JP 2005-048066 A JP 2005-048067 A JP 2006-131828 A JP 2006-160919 A

  As described above, it is possible to improve the fluidity of the polycarbonate to some extent by adding polylactic acid to the polycarbonate, but it is insufficient for application to thin-wall molding. That is, a resin composition having both fluidity and impact resistance that can be used for thin-wall molding and excellent moldability has been desired.

  The present invention intends to propose a resin capable of thin molding in fields where high heat resistance and impact resistance are required, such as home appliances, OA equipment, automobile parts, etc., for which polycarbonate resins have been conventionally used. is there.

  As a result of intensive studies in view of such a current situation, the present inventors have completed the present invention with high effects.

  In other words, the resin composition of the present invention has a lactic acid resin (A), a melt flow rate measured based on Japanese Industrial Standard JIS K7210 of 300 ° C. and 1.2 kg load, 60 g / 10 min or more, 90 g / 10 min or less, a resin composition containing an aromatic polycarbonate resin (B), a non-styrene rubber or elastomer (C), and a crystallization accelerator (D), the lactic acid resin (A) and The ratio of the aromatic polycarbonate resin (B) in the mixture of the aromatic polycarbonate resin (B) is 20% by mass or more and less than 45% by mass, and the lactic acid resin (A) and the 10 parts by mass or more of the non-styrene rubber or elastomer (C) with respect to 100 parts by mass of the total mass of the aromatic polycarbonate resin (B). The amount or less parts, the crystallization accelerator (D) 0.1 part by mass or more, and characterized by being in a proportion of less than 5 parts by weight.

Here, the relative crystallinity χc (A) of the lactic acid resin (A) of the injection molded article using the resin composition, the crystallization heat amount ΔHc (A) of the lactic acid resin (A), and the crystal melting The amount of heat ΔHm (A) is the following formula: χc (A) = {ΔHm (A) −ΔHc (A)} / ΔHm (A) ≧ 0.90
It is preferable to satisfy the relationship.

The injection-molded article of the present invention has a melt flow rate measured based on the lactic acid resin (A) and Japanese Industrial Standard JIS K7210 at a temperature of 300 ° C. and a load of 1.2 kg, which is 60 g / 10 min or more and 90 g / 10 min. A resin composition comprising the following aromatic polycarbonate resin (B), non-styrene rubber or elastomer (C), and a crystallization accelerator (D), the lactic acid resin (A) and the fragrance The proportion of the aromatic polycarbonate resin (B) in the mixture of the aromatic polycarbonate resin (B) is 20% by mass or more and less than 45% by mass, and the lactic acid resin (A) and the aromatic With respect to the total mass of the polycarbonate resin (B) being 100 parts by mass, the non-styrene rubber or elastomer (C) is 1 part by mass or more and 10 parts by mass or less, An injection-molded article using a resin composition obtained by blending the crystallization accelerator (D) at a ratio of 0.1 parts by mass or more and 5 parts by mass or less, wherein the relative ratio of the lactic acid resin (A) The crystallinity χc (A), the heat of crystallization ΔHc (A) of the lactic acid resin (A), and the heat of crystal fusion ΔHm (A) are expressed by the following formula: χc (A) = {ΔHm (A) −ΔHc (A)} / ΔHm (A) ≧ 0.90
It is characterized by satisfying the relationship.

  Here, the non-styrene rubber or elastomer is a shell made of at least one selected from the group consisting of acrylic rubber, acrylate copolymer, silicone rubber and methyl methacrylate, and from the group consisting of silicone rubber and acrylic rubber. A core-shell type rubber having at least one selected as a core is preferable.

  Alternatively, the non-styrene rubber or elastomer is preferably a polybutylene terephthalate / polytetramethylene glycol ether copolymer.

  In the present invention, the total mass of the lactic acid-based resin (A) and the aromatic polycarbonate-based resin (B) is 100 parts by mass of titanium oxide and is 0.5 parts by mass or more and 2.0 parts by mass or less. It is preferable to use a resin composition blended in proportions.

ADVANTAGE OF THE INVENTION According to this invention, the resin composition which has the fluidity | liquidity which can be molded thinly can be provided. Moreover, according to this invention, the injection molded object which has the outstanding heat resistance and impact resistance can be provided.

The present invention will be described below.
The resin composition according to the present invention contains a lactic acid resin (A), an aromatic polycarbonate resin (B), a non-styrene rubber or elastomer (C), and a crystallization accelerator (D) as main components. It consists of However, the aromatic polycarbonate resin (B) has a melt flow rate of 60 g / 10 min or more and 90 g / 10 min or less measured under conditions of 300 ° C. and 1.2 kg load based on Japanese Industrial Standard JIS K7210. is there.

(Lactic acid resin)
The lactic acid-based resin (A) used in the present invention includes poly (L-lactic acid) having a structural unit of L-lactic acid, poly (D-lactic acid) having a structural unit of D-lactic acid, a structural unit of L-lactic acid, and The main component is poly (DL-lactic acid), which is D-lactic acid, or a mixture thereof. In the present invention, the proportion of D-lactic acid is 0.1% or more and less than 3.0%, more preferably 0.5% or more and less than 2.0%. When the proportion of D-lactic acid is less than 0.1%, the productivity may decrease, and when it is 3% or more, the heat resistance of the injection-molded product may be difficult to obtain, and the application is limited. There is.

  Here, “main component” means to allow other components to be contained within a range that does not hinder the function of the main component resin, and in particular, specify the content ratio of the main component resin. However, the resin as the main component is 50% by mass or more, preferably 70% by mass or more, particularly preferably 90% by mass or more (100% by mass) in the resin composition (for example, lactic acid resin). Included). In the present invention, when “main component” is displayed other than the above, it has the same meaning as above unless otherwise specified.

  As a polymerization method for the lactic acid-based resin, known methods such as a condensation polymerization method and a ring-opening polymerization method can be employed. For example, in the condensation polymerization method, L-lactic acid or D-lactic acid, or a mixture thereof can be directly subjected to dehydration condensation polymerization to obtain a lactic acid resin having an arbitrary composition.

  In the ring-opening polymerization method, a lactic acid resin can be obtained from lactide, which is a cyclic dimer of lactic acid, by selecting an appropriate catalyst and using a polymerization regulator as necessary. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide composed of L-lactic acid and D-lactic acid. Accordingly, by mixing and polymerizing, a lactic acid resin having an arbitrary composition and crystallinity can be obtained.

Further, if necessary, such as improving heat resistance, a small amount of copolymer component within a range that does not impair the essential properties of the lactic acid resin, for example, within a range containing 90% by mass or more of the lactic acid resin component. Can be added. As a small amount of the copolymer component, a non-aliphatic dicarboxylic acid such as terephthalic acid and / or a non-aliphatic diol such as an ethylene oxide adduct of bisphenol A can be used.
Furthermore, for the purpose of increasing the molecular weight, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, or an acid anhydride can be used.

  The lactic acid-based resin may be a copolymer with an aliphatic diol and / or an aliphatic dicarboxylic acid, even if it is a copolymer with lactic acid and / or other hydroxycarboxylic acid units such as α-hydroxycarboxylic acid other than lactic acid. It may be a polymer.

  As other hydroxycarboxylic acid units, optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid Bifunctional aliphatic hydroxy-carboxylic acids such as 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, etc. Examples include lactones such as caprolactone, butyrolactone, and valerolactone.

  Examples of the aliphatic diol copolymerized with the lactic acid resin include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  The lactic acid resin used in the present invention preferably has a weight average molecular weight in the range of 50,000 to 400,000, more preferably 100,000 to 250,000. When the weight average molecular weight of the lactic acid-based resin is smaller than 50,000, practical physical properties such as mechanical properties and heat resistance are hardly expressed. When it is larger than 400,000, the melt viscosity is too high and the molding processability is poor. Sometimes.

  Representative examples of the lactic acid resin preferably used in the present invention include the “Lacia” series manufactured by Mitsui Chemicals, Inc., and the “Nature Works” series manufactured by Nature Works, etc. Can be mentioned.

  The relative crystallinity χc (A) of the lactic acid resin (A) in the injection molded product of the present invention, the crystallization heat amount ΔHc (A) of the lactic acid resin (A), and the heat of crystal fusion ΔHm (A) Needs to satisfy the relationship of the formula χc (A) = {ΔHm (A) −ΔHc (A)} / ΔHm (A) ≧ 0.90. When the relative crystallinity χc (A) of the lactic acid resin is less than 0.90, the impact resistance and heat resistance of the injection molded article cannot be sufficiently improved.

(Aromatic polycarbonate resin)
The aromatic polycarbonate resin used in the present invention means a resin whose main component is an aromatic polycarbonate. Here, the “main component” is as described above. For example, the resin as the main component is 50% by mass or more, preferably 70% by mass in the resin composition (here, aromatic polycarbonate resin). More preferably, it is 90% by mass or more (including 100% by mass).

  Examples of the aromatic polycarbonate resin preferably used in the present invention include those produced by interfacial polymerization, transesterification, pyridine, etc., using bisphenol A synthesized from phenol and acetone, bisphenol A and dicarboxylic acid derivatives, For example, polyester carbonate obtained by copolymerization with tere (iso) phthalic acid dichloride, derivatives of bisphenol A, for example, those obtained by polymerization of tetramethylene bisphenol A and the like can be mentioned. Examples of commercially available aromatic polycarbonate resins include the “Iupilon” series manufactured by Mitsubishi Engineering Plastics, the “Caliber” series manufactured by Sumitomo Dow.

  The aromatic polycarbonate resin (B) used in the present invention has a melt flow rate of 60 g / 10 min or more and 90 g / 10 min measured under the conditions of a measurement temperature of 300 ° C. and a load of 1.2 kg based on Japanese Industrial Standard JIS K7210. It is below, and it is more preferable that they are 70 g / 10min or more and 80 g / min or less. When the melt flow rate of the aromatic polycarbonate resin (B) is less than 60 g / 10 min, sufficient fluidity for thin-wall molding cannot be ensured. On the other hand, when the melt flow rate of the aromatic polycarbonate resin (B) is higher than 90 g / 10 min, the heat resistance of the aromatic polycarbonate resin is impaired, so that the heat resistance of the obtained injection molded article is sufficiently improved. I can't. In addition, as an index indicating sufficient fluidity for thin-wall molding, the melt flow rate (MFR) of the resin composition forming the injection molded body is measured at 230 ° C. under a load based on Japanese Industrial Standard JIS K7210. The value measured at 5 kg is preferably 10 g / 10 min or more and 20 g / 10 min or less.

(Non-styrene rubber or elastomer)
In order to improve the impact resistance of the resin composition comprising the lactic acid resin (A) and the aromatic polycarbonate resin (B), a non-styrene rubber or a non-styrene elastomer (C) is blended. When styrene rubber or styrene elastomer is blended, the crystallization speed of the lactic acid resin decreases, so that a great deal of time is spent on the crystallization treatment process for imparting heat resistance, and the productivity is significantly reduced. It ends up.

  Examples of the non-styrene rubber used in the present invention include acrylic rubber, acrylate copolymer, silicone rubber, and core-shell type rubber. Non-styrene elastomers have a high melting point and high crystallinity as a hard segment. Aromatic polyesters, and thermoplastic polyester elastomers composed of amorphous polyester, amorphous polyether or the like as a soft segment. The core-shell type rubber has at least one selected from the group consisting of acrylic rubber, acrylate copolymer, silicone rubber and methyl methacrylate as a shell, and at least one selected from the group consisting of silicone rubber and acrylic rubber. It is a core-shell type rubber having a core.

  As commercially available products, acrylic rubber includes “Kane Ace FM21” manufactured by Kaneka Co., Ltd., “Baraloid KM334” manufactured by Rohm and Haas, and the like. Examples include “Metablene P-530A” manufactured by Mitsubishi Rayon Co., Ltd., and core shell type rubbers include “W-450A” manufactured by Mitsubishi Rayon Co., Ltd., and “HIA-28S” manufactured by Rohm and Haas. As the thermoplastic polyester-based elastomer, “Primalloy A1800N”, “A1900N”, etc. manufactured by Mitsubishi Chemical Corporation can be used.

  In the present invention, a mixture of non-styrene rubber and non-styrene elastomer may be used as the non-styrene rubber or non-styrene elastomer (C). Further, the non-styrene rubber or non-styrene elastomer (C) may contain a non-styrene rubber and / or a non-styrene elastomer as a main component.

  The blending ratio of lactic acid resin (A), aromatic polycarbonate resin (B), non-styrene rubber or elastomer (C) is the ratio of component (B) in the mixture of component (A) and component (B). Is preferably 20% by mass or more and less than 45% by mass, more preferably 25% by mass or more and less than 44% by mass, and particularly preferably 30% by mass or more and less than 43% by mass. When the blending ratio of the component (B) is less than 20% by mass, the heat resistance of the obtained injection-molded product is lowered, so that the use may be very limited. Moreover, since fluidity | liquidity will fall when the mixture ratio of (B) component is 45 mass% or more, sufficient fluidity | liquidity cannot be ensured in order to perform the thin wall shaping | molding which is the main point of this invention.

  The blending ratio of the non-styrene rubber or elastomer (C) component is such that the component (C) is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the mixture of the component (A) and the component (B). It is preferable to mix | blend, It is further more preferable to mix | blend in the ratio of 2 to 8 mass parts, It is especially preferable to mix | blend in the ratio of 4 to 7 mass parts. When the blending ratio of the component (C) is less than 1 part by mass, the effect of improving the impact resistance cannot be obtained, and when it exceeds 10 parts by mass, the resulting molded article is softened and the heat resistance is lowered.

(Crystallization accelerator)
The crystallization accelerator (D) according to the present invention contains a crystallization accelerator as a main component. Preferred examples of the crystallization accelerator include inorganic compounds, aliphatic carboxylic acid amides, aliphatic carboxylates, difatty acid esters, animal and vegetable oils, fatty acids, aliphatic alcohols, waxes and the like. Moreover, you may mix and use these.

  Specific examples of the inorganic compound include talc, silica, kaolinite, calcium carbonate, and the like.

  Specific examples of the aliphatic carboxylic acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, N-stearyl stearic acid amide, methylol stearic acid amide, and methylol behenine. Acid amide, dimethylol oil amide, dimethyl lauric acid amide, dimethyl stearic acid amide, ethylene bis oleic acid amide, ethylene bis stearic acid amide, ethylene bis lauric acid amide, hexamethylene bis oleic acid amide, butylene bis stearic acid amide, m- Xylylene bis-stearic acid amide, trimesic acid tris (cyclohexyl amide), m-xylylene bis-12-hydroxystearic acid amide, N, N′-dioleyl adipic acid amide, N, N′-disteari Adipic acid amide, N, N′-distearylisophthalic acid amide, N, N′-distearyl terephthalic acid amide, N-butyl-N′-stearyl urea, N-propyl-N′-stearyl urea, N-allyl- N'-stearyl urea, N-stearyl-N'-stearyl urea and the like can be mentioned.

  Specific examples of the aliphatic carboxylate include sodium laurate, potassium laurate, potassium hydrogen laurate, magnesium laurate, calcium laurate, zinc laurate, silver laurate, lithium myristate, sodium myristate, Potassium hydrogen myristate, magnesium myristate, calcium myristate, zinc myristate, silver myristate, lithium palmitate, potassium palmitate, magnesium palmitate, calcium palmitate, zinc palmitate, copper palmitate, lead palmitate, palmitate Thallium acid, cobalt palmitate, sodium oleate, potassium oleate, magnesium oleate, calcium oleate, zinc oleate, lead oleate, tariu oleate , Copper oleate, nickel oleate, sodium stearate, lithium stearate, magnesium stearate, calcium stearate, barium stearate, aluminum stearate, thallium stearate, lead stearate, nickel stearate, beryllium stearate, isostearic acid Sodium, potassium isostearate, magnesium isostearate, calcium isostearate, barium isostearate, aluminum isostearate, zinc isostearate, nickel isostearate, sodium behenate, potassium behenate, magnesium behenate, calcium behenate, barium behenate, Aluminum behenate, zinc behenate, nickel behenate, sodium montanate Arm, potassium montanate, magnesium montanate, calcium montanate, barium montanate, aluminum montanate, zinc montanate, and montanic acid nickel, and the like.

  Specific examples of the difatty acid ester include dimethyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexyl adipate, dibutyl sebacate, di-2-ethylhexyl. Sebacate etc. are mentioned.

  Specific examples of the animal and vegetable oils include coconut oil, palm oil, linseed oil, epoxidized linseed oil, soybean oil, epoxidized soybean oil, cottonseed oil, rapeseed oil, tung oil, castor oil, beef tallow, squalane, lanolin, hydrogenated oil Etc.

  Specific examples of the fatty acid include stearic acid, lauric acid, palmitic acid, behenic acid, caprylic acid, capric acid, oleic acid, myristic acid, and montanic acid.

  Specific examples of the aliphatic alcohol include aliphatic monoalcohols such as pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl alcohol, seryl alcohol, and melyl alcohol, 1,6- Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, aliphatic polyhydric alcohols such as 1,10-decanediol, cyclopentane-1,2-diol, cyclohexane- Examples thereof include cyclic alcohols such as 1,2-diol and cyclohexane-1,4-diol.

  Specific examples of the waxes include animal waxes, plant waxes, mineral waxes, petroleum waxes and the like.

  The blending amount of the crystallization accelerator (D) may be blended at a ratio of 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the total mass of the component (A) and the component (B). Preferably, it is more preferably blended at a ratio of 1 part by mass or more and 3 parts by mass or less. When the blending ratio of the crystallization accelerator (D) is less than 0.1 parts by mass, the effect of promoting the crystallization rate cannot be obtained, and when it exceeds 5 parts by mass, the resulting molded article is softened and the mechanical properties are deteriorated. Etc. By blending the crystallization accelerator (D) within the above range, the crystallization speed can be improved without deteriorating mechanical properties, particularly mechanical properties such as impact resistance and heat resistance.

(Titanium oxide)
The resin composition according to the present invention can further contain titanium oxide. The compounding amount of titanium oxide is such that the total mass of lactic acid-based resin (A) and aromatic polycarbonate-based resin (B) is 100 parts by mass, and 0.5 to 2.0 parts by mass of titanium oxide. A ratio is preferred. By blending titanium oxide in such a range, the appearance of the pearl luster and the weld line portion can be improved without impairing the toning property of the obtained injection molded article.

(Carbodiimide compound)
In the present invention, a carbodiimide compound can be further blended in order to further improve the durability of the molded article obtained. As a carbodiimide compound used for this invention, what has the basic structure shown to the following general formula is mentioned as a preferable thing.
-(N = C = N-R-) n-
(In the above formula, R represents an organic bond unit, and can be, for example, aliphatic, alicyclic or aromatic. N represents an integer of 1 or more, and is usually appropriately between 1 and 50. When n is 2 or more, 2 or more R may be the same or different.)

  Specifically, for example, bis (dipropylphenyl) carbodiimide, poly (4,4′-diphenylmethanecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (tolylcarbodiimide), poly ( Examples of carbodiimide compounds include diisopropylphenylenecarbodiimide), poly (methyl-diisopropylphenylenecarbodiimide), poly (triisopropylphenylenecarbodiimide), and the like. These carbodiimide compounds can be used alone or in combination of two or more.

  Representative examples of commercially available carbodiimide compounds include the “Carbodilite” series manufactured by Nisshinbo Industries, Ltd. and the “Stabakuzol” series manufactured by Rhein Chemie.

  The compounding amount of the carbodiimide compound is preferably 0.1 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the resin composition for forming the injection molded body, and 0.5 parts by mass. As mentioned above, it is more preferable to mix at a ratio of 3 parts by mass or less. If the blending ratio of the carbodiimide compound is 0.1 parts by mass or more, an effect of improving the durability is obtained. If the blending ratio is 5 parts by mass or less, the heat resistance of the injection-molded product is lowered due to the plasticizing effect of the carbodiimide compound. Or, since there is no increase in viscosity due to excessive molecular weight improvement, there is no problem in moldability.

  In the resin composition according to the present invention, additives such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, and a dye can be blended within a range that does not impair the effects of the present invention. .

  Next, a method for forming an injection molded body using the resin composition according to the present invention will be described.

  Using raw materials such as lactic acid resin (A), aromatic polycarbonate resin (B), non-styrene rubber or elastomer (C), crystallization accelerator (D), and other additives, using an injection molding machine By directly mixing and injection molding, an injection molded body can be formed. Alternatively, a dry blended raw material is extruded into a strand shape using a twin screw extruder to produce pellets, and the pellets are again put into an injection molding machine and injection molded to form a molded body. .

  Regardless of which method is employed, it is necessary to consider a decrease in molecular weight due to decomposition of raw materials such as lactic acid-based resins, but the latter is preferably selected in order to uniformly mix the raw materials. For example, lactic acid resin (A), aromatic polycarbonate resin (B), non-styrene rubber or elastomer (C), crystallization accelerator (D), and other additives as necessary. After sufficiently drying to remove moisture, the mixture is melt-mixed using a twin screw extruder and extruded into a strand shape to produce pellets. Note that the melting point of the lactic acid resin varies depending on the composition ratio of the L-lactic acid structure and the D-lactic acid structure, the lactic acid resin (A), the aromatic polycarbonate resin (B), the non-styrene rubber, or the elastomer (C). It is preferable to appropriately select the melt extrusion temperature in consideration of the flow start temperature, flow characteristics, etc. of the mixed resin changing depending on the mixing ratio of the crystallization accelerator (D) and the like. In practice, a temperature range of 210 ° C. or higher and 240 ° C. or lower is usually selected.

  After the pellets prepared by the above method are sufficiently dried to remove moisture, injection molding is performed by the following method.

  The injection molding method is not particularly limited, but for example, an injection molding method, a gas assist molding method, an injection compression molding method, etc., generally employed when molding a thermoplastic resin can be employed. . Further, in accordance with other purposes, in-mold molding method, gas press molding method, two-color molding method, sandwich molding method, and the like can be adopted in addition to the above methods.

  The injection molding apparatus used is a general injection molding machine, gas assist molding machine, injection compression molding machine, etc., molding molds and incidental equipment used in these molding machines, mold temperature control device, raw material drying device Etc. In order to avoid thermal decomposition of the resin in the injection cylinder, it is preferable to mold the molten resin at a temperature of 210 ° C. or higher and 240 ° C. or lower.

  Next, crystallization treatment is performed in the mold during molding and / or after removal from the mold. From the viewpoint of productivity, when the crystallization speed of the resin forming the injection molded body is slow, it is preferable to perform the crystallization treatment after taking out from the mold, and when the crystallization speed is high, It is preferable to perform crystallization at.

  When crystallization is performed in the mold, the molten resin is filled in the heated mold and then held in the mold for a certain time. In this case, the mold temperature is preferably 80 ° C. or higher and 130 ° C. or lower, and more preferably 90 ° C. or higher and 120 ° C. or lower. The crystallization treatment time is preferably set as appropriate depending on the composition of the resin composition, the heat treatment temperature, etc. For example, the crystallization treatment time (cooling time) is preferably 1 second or more and 300 seconds or less. More preferably, it is 2 seconds or more and 60 seconds or less.

  Moreover, when crystallizing after taking out a molded object from a metal mold | die, 60 degreeC or more and 130 degrees C or less are preferable, and 70 degreeC or more and 100 degrees C or less are more preferable. When the heat treatment temperature is lower than 60 ° C., crystallization may not proceed in the molding step, and when it is higher than 130 ° C., deformation or shrinkage may occur when the molded body is cooled.

  The crystallization treatment time is preferably set as appropriate according to the composition of the resin composition, the heat treatment temperature, etc. For example, when the heat treatment temperature is 70 ° C., the crystallization treatment time is 15 minutes or more and 5 hours or less. Preferably, when the heat treatment temperature is 130 ° C., the crystallization treatment time is preferably 10 seconds or longer and 30 minutes or shorter.

  As a crystallization treatment method, the mold temperature is raised in advance and crystallized in the mold, or after the injection molded body is taken out from the mold in an amorphous state, hot air, steam, hot water, Examples thereof include a method of crystallizing with an infrared heater, an IH heater or the like. When the crystallization treatment is performed, the molded body may be fixed without being fixed. However, in order to prevent deformation of the molded body, it is preferable to fix the molded body with a mold, a resin mold or the like. In consideration of productivity, heat treatment may be performed in a packed state.

  As described above, in the present invention, the lactic acid resin of the molded body needs to satisfy a specific formula, and the relative crystallinity χc (A) of the lactic acid resin is 0.90 or more. is necessary. The injection molded article of the present invention is preferably subjected to a crystallization treatment so as to satisfy this relational expression. For example, it is preferable to perform the crystallization treatment at 80 ° C. or higher and 130 ° C. or lower. By setting the relative crystallinity χc (A) to 0.90 or more, it is possible to realize an injection-molded article having excellent heat resistance applicable to a wide range of uses such as home appliances, OA equipment, and automobile parts.

The resin composition according to the present invention has fluidity applicable to thin-wall molding, and an injection-molded product formed using this resin composition has excellent heat resistance and impact resistance. Therefore, this molded body is used for refrigerator pan, door handle, washing machine lid, washing tub, refrigerator shelf, inner box, decorative plate, air conditioner indoor unit, outdoor unit housing, panel, grill, damper, cleaning Machine housing, air inlet, control switch, wheel, audio visual equipment housing, control panel, tray, microwave oven, rice cooker, pot and other household appliances, copier, facsimile, printer housing, cassette, cartridge It can be used for automobile parts such as OA equipment such as front grille, emblem, bumper, wheel cover, door mirror housing, door handle, mat guard, lamp housing, roof rail, pillar cover, antenna holder, wiper, air spoiler.

  The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical scope of the present invention. Each example and each comparative example were evaluated and measured by the following methods.

(1) Melt flow rate (MFR)
The melt flow rate was evaluated as an indicator of fluidity. That is, based on Japanese Industrial Standard JIS K7210, the melt flow rate (MFR) of the resin was measured under the measurement conditions of a temperature of 230 ° C. and a load of 5 kg.

(2) Appearance The pearl luster on the surface of a plate material having a length of 120 mm, a width of 11 mm, and a thickness of 3 mm was visually observed and evaluated based on the following evaluation criteria.

Evaluation criteria:
× Clearly pearly gloss △ Slightly pearly glossy ○ Not pearly glossy

(3) Relative crystallinity Based on Japanese Industrial Standard JIS K7121, an approximately 10 mg sample is cut out from an injection-molded product, and DSC-7 manufactured by Perkin Elmer is used at a rate of 10 ° C / min. The temperature was measured up to 0 ° C., and the heat of crystallization ΔHc (A) and the heat of crystal fusion ΔHm (A) of the lactic acid resin were read from the obtained thermogram. From the obtained value, the relative crystallinity χc (A) was calculated by the following formula.
χc (A) = {ΔHm (A) −ΔHc (A)} / ΔHm (A)

(4) Izod impact strength Izod impact strength was evaluated as an index of impact resistance. Based on Japanese Industrial Standard JIS K7110, No. 2 A test piece (notched, length 64 mm × width 12.7 mm × thickness 4 mm) was prepared, and 23 using JISL-D manufactured by Toyo Seiki Seisakusho Co., Ltd. The Izod impact strength at 0 ° C. was measured.

(5) Deflection temperature under load As an index of heat resistance, the deflection temperature under load was evaluated. A test piece having a length of 120 mm, a width of 11 mm, and a thickness of 3 mm was prepared based on the Japanese Industrial Standard JIS K7191 Method A, and the deflection temperature under load was measured using S-3M manufactured by Toyo Seiki Co., Ltd. The measurement was performed under the conditions of a flatwise direction and a bending stress of 1.8 MPa applied to the test piece.

(Example 1)
As a lactic acid resin (A), Nature Works 4032D (D lactic acid ratio: 1.4%, weight average molecular weight: 200,000) manufactured by Nature Works, melt flow rate at 300 ° C. and 1.2 kg load based on JIS K7210 As an aromatic polycarbonate-based resin (B) having an A of 60 or more and 90 or less, Asahi Kasei Co., Ltd. Wonderlite PC-175 (300 ° C. based on JIS K7210, melt flow rate at 1.2 kg load is 65 g / 10 min), As non-styrene rubber or elastomer (C), Methrene W-450A (core shell rubber made of methyl methacrylate and 2-ethylhexyl acrylate / butyl acrylate copolymer) manufactured by Mitsubishi Rayon Co., Ltd., and crystallization accelerator (D ) Nihon Talc Co., Ltd. Made in SG-95 (talc, average particle diameter 2.5 [mu] m) were used. Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, and SG-95 were dry blended at a mass ratio of 60: 40: 3: 1, and then the same size of 40 mmφ manufactured by Mitsubishi Heavy Industries, Ltd. It was compounded at 230 ° C. using a twin screw extruder to form a pellet. Using the obtained pellets, an injection molding machine IS50E (screw diameter: 25 mm) manufactured by Toshiba Machine Co., Ltd., as a test piece for evaluation of appearance and relative crystallinity, a test piece having a length of 120 mm, a width of 11 mm and a thickness of 3 mm As a test piece for evaluation of Izod impact strength, a test piece of length 64 mm × width 12.7 mm × thickness 4 mm, and as a test piece for evaluation of deflection temperature under load, length 120 mm × width 11 mm × thickness 3 mm A test piece was obtained by injection molding. However, main molding conditions are as follows.

1) Temperature conditions: Cylinder temperature (230 ° C) Mold temperature (40 ° C)
2) Injection conditions: Injection pressure (115 MPa) Holding pressure (55 MPa)
3) Measurement conditions: Screw rotation speed (65 rpm) Back pressure (15 MPa)

  Next, the obtained test piece was left still in a baking test apparatus (DKS-5S manufactured by Daiei Kagaku Seiki Seisakusho) and heat-treated at 80 ° C. for 20 minutes. Using this test piece, the appearance, relative crystallinity, Izod impact strength, and deflection temperature under load were evaluated and measured. The results are shown in Table 1.

(Example 2)
The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, and SG-95 is 60: 40: 5: 1. The test piece was injection-molded and heat-treated in the same manner as in Example 1 except that dry blending was performed so that an evaluation test piece was produced. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, and SG-95 is 60: 40: 10: 1. A test piece was injection-molded and heat-treated in the same manner as in Example 1 except that dry blending was performed, and an evaluation test piece was prepared. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4
As non-styrene rubber or elastomer (C), Kaneace FM21 (butyl acrylate / methyl methacrylate copolymer) manufactured by Kaneka Co., Ltd. is used, and the blending amount of each raw material of pellets used for forming an injection-molded product is set to Nature. The same method as in Example 1 except that the weight ratio of Works 4032D, Wonderlite PC-175, Kane Ace FM21, and SG-95 was changed to a ratio of 60: 40: 5: 1 and dry blended. Then, the test piece was injection molded and heat-treated to produce a test piece for evaluation. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
As the non-styrene rubber or elastomer (C), Primalloy A1800N (polybutylene terephthalate / polytetramethylene glycol ether copolymer) manufactured by Mitsubishi Chemical Corporation is used, and each raw material of pellets used for forming an injection molded product Example except that the blending amount was changed so that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Primalloy A1800N, and SG-95 was 60: 40: 5: 1 and dry blended. In the same manner as in No. 1, a test piece was injection-molded and heat-treated to produce an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 6)
The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, and SG-95 is a ratio of 80: 20: 5: 1. A test piece was injection-molded and heat-treated in the same manner as in Example 1 except that dry blending was performed to prepare a test piece for evaluation. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Example 7)
Further, titanium oxide (manufactured by Nacalai Tesque) was used. The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, SG-95, and titanium oxide is 60: 40: 5: 1. A test piece was injection-molded and heat-treated by the same method as in Example 1 except that dry blending was performed at a ratio of 1 to prepare an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
As the aromatic polycarbonate, Wonderlite PC-122 manufactured by Asahi Kasei Co., Ltd. (300 ° C. based on JIS K7210, melt flow rate at 1.2 kg load is 22 g / 10 min) was used. The blending amount of each raw material of the pellets used for forming the injection-molded body is such that Nature Works 4032D, Wonderlite PC-122, Metabrene W450A, and SG-95 have a mass ratio of 60: 40: 5: 1. A test piece was injection-molded and heat-treated in the same manner as in Example 1 except that it was dry-blended to produce an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
Dry blend the blending amount of each raw material of the pellets used for forming the injection molded body so that the mass ratio of Nature Works 4032D, Wonderlite PC-175, and SG-95 is 60: 40: 1. A test piece was injection molded and heat-treated in the same manner as in Example 1 except that an evaluation test piece was produced. About the obtained test piece, evaluation similar to an Example etc. were performed. The results are shown in Table 1.

(Comparative Example 3)
Except for dry blending, the blending amount of each raw material of the pellets used for forming the injection molded body is such that the mass ratio of Nature Works 4032D, Metabrene W450A, and SG-95 is a ratio of 100: 5: 1. In the same manner as in Example 1, a test piece was injection-molded and heat-treated to produce an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene W450A, and SG-95 is 40: 60: 5: 1. A test piece was injection-molded and heat-treated in the same manner as in Example 1 except that dry blending was performed to prepare a test piece for evaluation. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 5)
As an elastomer containing styrene, Methbrene C223A (core shell rubber made of methyl methacrylate / styrene copolymer and butadiene rubber) manufactured by Mitsubishi Rayon Co., Ltd. was used. The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Metabrene C223A, and SG-95 is a ratio of 60: 40: 5: 1. The test piece was injection-purified and heat-treated in the same manner as in Example 1 except that dry blending was performed, and a test piece for evaluation was produced. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 6)
As the elastomer containing styrene, Primalloy A1500N (polybutylene terephthalate / polytetramethylene glycol ether / styrene elastomer copolymer) manufactured by Mitsubishi Chemical Corporation was used. The blending amount of each raw material of the pellets used for forming the injection-molded body is such that the mass ratio of Nature Works 4032D, Wonderlite PC-175, Primalloy A1500N, and SG-95 is a ratio of 60: 40: 5: 1. After dry blending, a test piece was prepared and heat-treated in the same manner as in Example 1 to prepare an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 7)
The blending amount of each raw material of the pellets used for forming the injection molded body was dry blended so that the mass ratio of Nature Works 4032D, Wonderlite PC-175, and Metabrene W450A was 60: 40: 5. Except for the above, a test piece was injection molded by the same method as in Example 1 and heat-treated to prepare an evaluation test piece. The obtained test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

  As is apparent from Table 1, the injection-molded articles of Examples 1 to 6 using the resin composition according to the present invention have fluidity that can be adapted to thin-wall molding, and have a good appearance evaluation. It was found that the relative crystallinity of the lactic acid-based resin was 0.9 or more, and it was excellent in impact resistance and heat resistance. In addition, the injection-molded body of Example 7 has fluidity that can be adapted to thin-wall molding, the relative crystallinity of the lactic acid resin is 0.9 or more, and has excellent impact resistance and heat resistance. there were. In addition, since Example 7 contains titanium oxide, pearl luster is not recognized and it has the characteristic excellent in the use which makes an external appearance a problem.

  Further, as is apparent from Table 1, it was found that the resin compositions of Comparative Examples 1 and 4 had low melt flow rates and could not be applied to thin wall molding. The injection molded articles of Comparative Examples 2 and 5 to 7 had low impact strength and were difficult to put into practical use. Moreover, it turned out that the injection-molded body of Comparative Examples 3 and 5 to 7 has insufficient heat resistance.

  The injection-molded article of the present invention has excellent heat resistance, impact resistance, and fluidity, so that it is an OA for refrigerators, washing machines, air conditioner indoor units, outdoor units, vacuum cleaners, copiers, facsimiles, etc. It can be used for automobile parts such as equipment and bumpers.

Claims (5)

  Lactic acid-based resin (A), an aromatic polycarbonate-based resin having a melt flow rate measured based on Japanese Industrial Standard JIS K7210 of 60 g / 10 min or more and 90 g / 10 min or less under the conditions of 300 ° C. and 1.2 kg load (B), a non-styrenic rubber or elastomer (C), and a resin composition containing a crystallization accelerator (D), comprising the lactic acid resin (A) and the aromatic polycarbonate resin (B). The ratio of the aromatic polycarbonate resin (B) in the mixture is 20% by mass or more and less than 45% by mass, and the total of the lactic acid resin (A) and the aromatic polycarbonate resin (B) 1 to 10 parts by mass of the non-styrene rubber or elastomer (C) with respect to 100 parts by mass of the crystallization accelerator (D) 0.1 part by mass or more, resin composition characterized by comprising in proportions of less than 5 parts by weight. Lactic acid-based resin (A), an aromatic polycarbonate-based resin having a melt flow rate measured based on Japanese Industrial Standard JIS K7210 of 60 g / 10 min or more and 90 g / 10 min or less under the conditions of 300 ° C. and 1.2 kg load (B), a non-styrenic rubber or elastomer (C), and a resin composition containing a crystallization accelerator (D), comprising the lactic acid resin (A) and the aromatic polycarbonate resin (B). The ratio of the aromatic polycarbonate resin (B) in the mixture is 20% by mass or more and less than 45% by mass, and the total of the lactic acid resin (A) and the aromatic polycarbonate resin (B) The non-styrene rubber or elastomer (C) is 1 part by mass or more and 10 parts by mass or less, and the crystallization accelerator (D) is 100 parts by mass. An injection-molded article using a resin composition blended at a ratio of 0.1 parts by mass or more and 5 parts by mass or less, wherein the lactic acid-based resin (A) has a relative crystallinity χc (A), The crystallization heat amount ΔHc (A) and the crystal melting heat amount ΔHm (A) of the lactic acid resin (A) are expressed by the following formula: χc (A) = {ΔHm (A) −ΔHc (A)} / ΔHm (A) ≧ 0.90
An injection-molded body that satisfies the above relationship.   The non-styrene rubber or elastomer is at least one selected from the group consisting of acrylic rubber, acrylate copolymer, silicone rubber and methyl methacrylate, and is at least selected from the group consisting of silicone rubber and acrylic rubber. The injection-molded article according to claim 2, which is a core-shell type rubber having one kind as a core.   The injection-molded article according to claim 2, wherein the non-styrene rubber or elastomer is a polybutylene terephthalate-polytetramethylene glycol ether copolymer.   Resin in which the total mass of the lactic acid-based resin (A) and the aromatic polycarbonate-based resin (B) is 100 parts by mass of titanium oxide in a proportion of 0.5 parts by mass or more and 2.0 parts by mass or less. The injection-molded article according to any one of claims 2 to 4, wherein the composition is used.