JP6065512B2 - Resin composition and molded product formed by molding the resin composition - Google Patents

Description

  The present invention relates to a resin composition characterized by having a high specific gravity, excellent moldability, and moderate biodegradability, and a molded product formed by molding the composition.

  In recent years, biodegradable resins have attracted a great deal of attention worldwide due to waste disposal problems, and various biodegradable resins have been commercialized. Among them, polylactic acid is the most frequently used biodegradable resin, but has a low crystallization rate and a problem in moldability, and has excellent rigidity but poor impact resistance and tends to be slow in biodegradability.

  Various studies have been made to solve the above problems, for example, it has been proposed to use an aromatic aliphatic copolymer polyester resin such as polybutylene adipate terephthalate, although it has excellent impact resistance, The rigidity is low and biodegradation tends to be slow (see, for example, Patent Document 1).

  Aliphatic polyester resins such as polybutylene succinate and polybutylene succinate adipate are also known as biodegradable resins, but biodegradation tends to be faster than polylactic acid resins.

  Therefore, a biodegradable resin composition containing a specific amount of a polylactic acid polymer with respect to an aliphatic polyester resin has been proposed, but the biodegradation is slower than the aliphatic polyester resin, but the impact resistance is reduced. However, the balance between rigidity and impact resistance is insufficient (see, for example, Patent Document 2).

  On the other hand, high specific gravity resin compositions are required in various fields. In particular, if the above-described biodegradability and high specific gravity can be compatible, it is considered that the uses of the biodegradable resin are further expanded. However, in order to obtain a resin composition having a high specific gravity, for example, when an appropriate amount of an inorganic filler having a high specific gravity is contained in the resin, the fluidity is lowered, and therefore, moldability such as generation of bubbles, burrs and sink marks is reduced. A problem occurs.

  Thus, conventionally, it has been very difficult to obtain a resin composition or a molded product having moderate biodegradability, high specific gravity, and excellent moldability.

Special table 2001-500907 International Publication No. 2002/094935 Pamphlet

  Therefore, the present invention has an object to provide a resin composition characterized by having an appropriate biodegradability, a high specific gravity, and excellent moldability, and a molded product formed by molding the resin composition. And

  In general, “biodegradability” is considered to be degradation involving microorganisms, but in the present application, it refers to a characteristic in which weight loss is observed when taken out by being buried in soil under specific conditions. “Moderate biodegradability” means that biodegradability is neither fast nor slow. Fast biodegradability is a problem from the viewpoint of durability, and slow biodegradability is a waste treatment. It is a problem from the point of view. Biodegradability is known to be affected by external factors such as soil temperature and moisture content.

  In the present application, “appropriate biodegradability” means that the biodegradability is 14 to 28 days when the change in appearance is evaluated according to the criteria described below under a specific condition. Here, the specific conditions are a soil temperature of 40 ° C. and a soil moisture content of 20% by weight. The specific soil is the soil in the Yokkaichi Plant of Mitsubishi Chemical Corporation.

  As a result of earnest research to solve the above-mentioned problems, the present inventor has formed a high specific gravity by containing a specific amount of an aliphatic polyester resin, an inorganic filler having a specific gravity of a predetermined value, and a plasticizer. The present inventors have found that a resin composition having excellent properties and moderate biodegradability and a molded product formed by molding the resin composition can be provided.

That is, the gist of the present invention is as follows.
[1]
In the resin composition containing the aliphatic polyester resin (A), the inorganic filler (B) and the plasticizer (C), the specific gravity of the inorganic filler (B) is 2.5 or more, and the aliphatic polyester resin (A) A resin composition comprising 50 to 550 parts by weight of an inorganic filler (B) and 0.01 to 20 parts by weight of a plasticizer (C) with respect to 100 parts by weight.
[2]
The resin composition as described in [1], further containing 0.01 to 10 parts by weight of a fatty acid metal salt (D) with respect to 100 parts by weight of the aliphatic polyester resin (A).
[3]
The inorganic filler (B) is a mixture of an inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 and an inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0. The resin composition according to [1] or [2], which is characterized in that it exists.
[4]
The inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 is at least one selected from the group consisting of talc, mica, calcium carbonate, aluminum hydroxide, calcium hydroxide, and magnesium hydroxide. And the inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0 is at least one selected from the group consisting of barium sulfate, barium carbonate and titanium oxide [3] The resin composition described in 1.
[5]
The resin composition according to any one of [2] to [4], wherein the fatty acid metal salt (D) is at least one selected from the group consisting of calcium stearate, magnesium stearate, and calcium laurate.
[6]
The aliphatic polyester resin (A) contains an aliphatic diol unit and an aliphatic dicarboxylic acid unit. The resin composition according to any one of [1] to [5],
[7]
[1] A molded product obtained by molding the resin composition according to any one of [6].
[8]
A spherical molded product obtained by molding the resin composition according to any one of [1] to [6].

  According to the present invention, it is possible to provide a resin composition having moderate biodegradability, high specific gravity and excellent moldability, and a molded product formed by molding the resin composition.

1. Resin Composition The resin composition of the present invention contains an aliphatic polyester resin (A), an inorganic filler (B), and a plasticizer (C), and further contains a fatty acid metal salt (D) as necessary. It contains. Here, when the content ratio of the aliphatic metal salt (D) is large, the moldability of the resin composition tends to be insufficient.

  In the resin composition of the present invention, the content ratios of the aliphatic polyester resin (A), the inorganic filler (B) and the plasticizer (C) and the fatty acid metal salt (D) added as necessary are as follows. It is as follows.

  The content ratio of the inorganic filler (B) is 50 to 550 parts by weight, preferably 60 to 500 parts by weight, more preferably 70 to 450 parts by weight, based on 100 parts by weight of the aliphatic polyester resin (A). The amount is preferably 80 to 420 parts by weight, particularly preferably 90 to 400 parts by weight. If the content ratio is too small, a resin composition having a high specific gravity tends to be difficult to obtain, and if the content ratio is too large, the moldability of the resin composition tends to be insufficient.

  The content ratio of the plasticizer (C) is 0.01 to 20 parts by weight, preferably 0.05 to 18 parts by weight, more preferably 0.1 to 0.1 parts by weight based on 100 parts by weight of the aliphatic polyester resin (A). 16 parts by weight, more preferably 0.2 to 14 parts by weight, particularly preferably 0.3 to 12 parts by weight. If the content ratio is too small or too large, there is a tendency for problems in the moldability of the resin composition.

  The content ratio of the fatty acid metal salt (D) contained as necessary is 0.01 to 10 parts by weight, preferably 0.02 to 8 parts by weight, with respect to 100 parts by weight of the aliphatic polyester resin (A). More preferably, it is 0.03-6 weight part, More preferably, it is 0.04-4 weight part, Especially preferably, it is 0.05-2 weight part. When the content ratio is within this range, the moldability of the resin composition tends to be better.

  The melt flow rate (MFR) value of the resin composition of the present invention is measured at a cylinder temperature of 190 ° C. and a load of 2.16 kg using a melt indexer in accordance with JIS K7210 from the viewpoint of moldability. It is preferable that it is -150g / 10min, More preferably, it is 35-140g / 10min, More preferably, it is 40-130g / 10min, Especially preferably, it is 45-120g / 10min. In the present invention, by setting the content ratio of the aliphatic polyester resin (A), the inorganic filler (B) and the plasticizer (C) within the above range, the melt flow rate of the resin composition is set within a predetermined range. The moldability can be improved.

  The value of specific gravity of the resin composition of the present invention is preferably 1.5 to 3.0, more preferably 1.6 to 2 as measured according to JIS K7112 A method (in-water replacement method). 0.9, more preferably 1.7 to 2.8, particularly preferably 1.8 to 2.7. When the specific gravity of the resin composition is within the range, it is suitable as a resin composition used for a molded product having a high specific gravity. When the specific gravity of the resin composition is small, the weight of a molded product obtained from the resin composition is small, and automobile members and the like are required to have a low specific gravity in order to improve fuel efficiency. On the other hand, there are uses that require molded articles with a high specific gravity to give a feeling of weight or function, for example, equipment members such as OA equipment and housings for home appliances, mechanical members such as gears, and shooting competitions. Goods such as plastic bullets can be raised. If the specific gravity is too small, the specific gravity of a molded product obtained by molding the resin composition is reduced and the application field is limited. If the specific gravity is too large, the moldability of the resin composition tends to be low. Is also not preferred.

1.1. Aliphatic polyester resin (A)
The aliphatic polyester resin (A) is a resin in which the molar ratio of the aliphatic structure is the maximum ratio with respect to the entire structure. For example, the aliphatic aromatic resin partially has an aromatic structure in addition to the aliphatic structure. Polyester may be used. More specifically, aliphatic polyesters, aliphatic aromatic polyesters, and mixtures thereof can be mentioned. In particular, in the present invention, the aliphatic polyester resin (A) preferably contains an aliphatic diol unit and an aliphatic dicarboxylic acid unit.

  More specifically, the aliphatic polyester resin (A) is an aliphatic polyester containing an aliphatic diol unit represented by the following formula (1) and an aliphatic dicarboxylic acid unit represented by the following formula (2). Resin.

—O—R ¹ —O— (1)
^-OC-R 2 -CO- (2)
(In Formula (1), R ¹ represents a divalent aliphatic hydrocarbon group. In Formula (2), R ² represents a divalent aliphatic hydrocarbon group.)

  Although it does not specifically limit as aliphatic diol which gives the diol unit of Formula (1), From a viewpoint of a moldability or mechanical strength, a C2-C10 aliphatic diol is preferable, C4-C6 is preferable. Aliphatic diols are particularly preferred. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like can be mentioned, among which 1,4-butanediol is particularly preferable. Two or more kinds of the above aliphatic diols can be used.

  Although it does not specifically limit as a dicarboxylic acid component which gives the dicarboxylic acid unit of Formula (2), C2-C40 aliphatic dicarboxylic acid is preferable, C4-C10 aliphatic dicarboxylic acid is especially preferable. preferable. For example, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid and the like can be mentioned, among which succinic acid, adipic acid and sebacic acid are preferable, and succinic acid and adipic acid are particularly preferable. Two or more kinds of the aliphatic carboxylic acids can be used.

  When the aliphatic dicarboxylic acid composed of an aliphatic dicarboxylic acid unit is succinic acid, the resin composition and the resin composition are obtained by molding the resin composition by keeping the amount of succinic acid-derived structural units within a predetermined range. Appropriate biodegradability can be imparted to the molded article under normal conditions. The proportion of structural units derived from succinic acid in the total aliphatic dicarboxylic acid units is preferably 50 to 95 mol%, more preferably 55 to 90 mol%, still more preferably 60 to 87 mol%.

  Further, when the aliphatic dicarboxylic acid composed of the aliphatic dicarboxylic acid unit is succinic acid and adipic acid, the amount of structural units derived from succinic acid and adipic acid is within a predetermined range, whereby the resin composition and the With respect to a molded product obtained by molding the resin composition, it becomes easier to impart appropriate biodegradability and impact resistance under normal conditions. The proportion of structural units derived from succinic acid in the total aliphatic dicarboxylic acid units is preferably 50 to 95 mol%, more preferably 60 to 93 mol%, still more preferably 70 to 90 mol%, and the total aliphatic dicarboxylic acid The proportion of the structural unit derived from adipic acid in the unit is preferably 5 to 50 mol%, more preferably 7 to 40 mol%, still more preferably 10 to 30 mol%.

  Furthermore, the aliphatic polyester resin (A) in the present invention may have a repeating unit derived from an aliphatic oxycarboxylic acid (aliphatic oxycarboxylic acid unit). Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy- Examples include 3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid and the like, or lower alkyl esters or intramolecular esters thereof. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be solid, liquid, or aqueous solution. Of these, lactic acid or glycolic acid is particularly preferred. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more.

  The amount of the aliphatic oxycarboxylic acid unit is preferably 20 mol% or less, more preferably 10 mol% or less in the total aliphatic dicarboxylic acid unit of the aliphatic polyester resin (A) from the viewpoint of moldability. More preferably, it is 5 mol% or less.

  In addition, the aliphatic polyester resin (A) in the present invention may have a chain length extended by a coupling agent or the like.

  Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound, acid anhydride, and the like. Specifically, 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, hydrogen Xylylene diisocyanate, hexamethylene diisocyanate and the like. It is preferable that these addition amounts are 0.1-5 weight part with respect to 100 weight part of aliphatic polyester-type resin (A).

  The aliphatic polyester resin (A) used in the present invention can be produced by a known method. For example, a general method of melt polymerization in which an esterification reaction and / or transesterification reaction between the aliphatic dicarboxylic acid and the aliphatic diol is performed, and then a polycondensation reaction under reduced pressure is performed, or an organic solvent is used. Although it can manufacture also by the well-known solution heating dehydration condensation method used, the method of manufacturing by the melt polymerization performed without a solvent from a viewpoint of economical efficiency or the simplicity of a manufacturing process is preferable.

  The average molecular weight of the aliphatic polyester resin (A) can be measured by gel permeation chromatography (GPC), and the weight average molecular weight of polystyrene as a standard substance is preferably 10,000 or more and 1,000. However, since it is advantageous in terms of formability and mechanical strength, it is more preferably 20,000 or more and 500,000 or less, and further preferably 50,000 or more and 400,000 or less.

  When the melt flow rate (MFR) of the aliphatic polyester resin (A) is measured at a cylinder temperature of 190 ° C. and a load of 2.16 kg using a melt indexer in accordance with JIS K7210, preferably 0.1 g / It is 10 minutes or more, preferably 150 g / 10 minutes or less. From the viewpoint of moldability and mechanical strength, it is more preferably 120 g / 10 min or less, and still more preferably 100 g / 10 min or less.

  The lower limit of the melting point of the aliphatic polyester resin (A) is preferably 70 ° C or higher, more preferably 75 ° C or higher, and the upper limit is preferably 170 ° C or lower, more preferably 119 ° C or lower, most preferably. It is less than 100 ° C. When there are a plurality of melting points, at least one melting point is preferably within the above range.

1.2. Inorganic filler (B)
The inorganic filler (B) in the present invention is an inorganic filler having a specific gravity of 2.5 or more. By using such an inorganic filler (B), the specific gravity of the resin composition can be suitably increased.

  The inorganic filler (B) may be fibrous, granular, or plate-like depending on its shape, and is particularly preferably granular or plate-like. Mineral particles such as talc, zeolite, diatomaceous earth, kaolin, clay, silica, barium sulfate, quartz powder, etc., metal carbonate particles such as calcium carbonate, magnesium carbonate, barium carbonate, heavy calcium carbonate Metal silicate particles such as calcium silicate, aluminum silicate and magnesium silicate, metal oxide particles such as alumina, silica, zinc oxide and titanium oxide, metal hydroxide particles such as aluminum hydroxide, calcium hydroxide and magnesium hydroxide And carbon particles such as carbon black. Moreover, mica is mentioned as a plate-shaped inorganic filler.

  The dispersion state of the inorganic filler in the resin composition or in the molded product is 0.08 to 25 μm in terms of number average particle diameter, more preferably 0.1 μm to 5 μm. When it deviates from this range, the addition effect of the said inorganic filler will become low. Incidentally, the “number average particle size” is a morphological photograph obtained by cutting out a flaky sample with a microtome or the like from a molded product obtained by molding the resin composition of the present invention and appropriately adjusting the magnification of a scanning electron microscope. This is a value obtained by image analysis.

  The inorganic filler (B) used in the present invention includes an inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 and an inorganic filler (B-) having a specific gravity of 3.5 or more and less than 5.0. It is preferable that it is a mixture with 2). Thereby, a resin composition having a relatively wide specific gravity range can be easily obtained, and the uneven distribution of the inorganic filler in the resin composition can be suppressed, and the density can be made uniform when formed into a molded product.

  The inorganic filler (B) used in the present invention includes an inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 and an inorganic filler (B-) having a specific gravity of 3.5 or more and less than 5.0. 2), the inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 is from talc, mica, calcium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide. And at least one selected from the group consisting of barium sulfate, barium carbonate, and titanium oxide as the inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0. More preferably, it is a seed. From the viewpoint of economy, the inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 is talc, and the inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0. Is more preferably barium sulfate.

1.3. Plasticizer (C)
As the plasticizer (C) used in the present invention, known ones can be used without particular limitation, and examples thereof include monohydric alcohols, polyhydric alcohols, partial esters or partial ethers of polyhydric alcohols. It is done. Among these, sorbitol, pentaerythritol, trimethylolpropane, trimethylolethane, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1, 6-hexanediol, 1,8-octanediol, 1,9-nanonediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol , Polypropylene glycol, glycerol, glycerol monoalkyl ester, glycerol dialkyl ester, glycerol monoalkyl ether, glycerol dialkyl ether, diglycerol, diglycerol alkyl Ester etc., more preferably ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, glycerin monoester, sorbitol or pentaerythritol, particularly preferably glycerin, sorbitol, pentaerythritol, propylene glycol or ethylene glycol . Two or more types can be used in combination. Among these, glycerin is particularly preferable from the viewpoint of moldability.

1.4. Fatty acid metal salt (D)
In the present invention, the fatty acid metal salt (D) contained as required is particularly preferably one having 12 to 30 carbon atoms. Moreover, as a metal seed | species, generally the carboxylate of the 1st-14th group metal element except a hydrogen and carbon in a periodic table is preferable. Particularly preferred are alkali metals, alkaline earth metals, and transition metals of the third to fourth periods of the periodic table. Most preferably, alkaline earth metals of the third to fourth periods are suitably selected. Among the above, the alkali metal carboxylate may deteriorate the resin, depending on the amount used, and may deteriorate the hydrolysis resistance and mechanical properties during the production or after the molding. If the number of carbon atoms of the fatty acid is less than the above lower limit, smoke, roll dirt, and bleed-out may be a problem during molding, and if it exceeds the upper limit, odor may be a problem due to thermal decomposition during molding.

  Examples of the fatty acid metal salt include sodium laurate, potassium laurate, potassium hydrogen laurate, magnesium laurate, calcium laurate, zinc laurate, silver laurate, lithium laurate, lithium myristate, sodium myristate, Potassium hydrogen myristate, magnesium myristate, calcium myristate, zinc myristate, silver myristate, aluminum myristate, lithium palmitate, potassium palmitate, magnesium palmitate, calcium palmitate, zinc palmitate, copper palmitate, palmitate Lead acid, thallium palmitate, cobalt palmitate, sodium oleate, potassium oleate, magnesium oleate, calcium oleate, zinc oleate Lead oleate, thallium 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, sodium isostearate, potassium isostearate, magnesium isostearate, calcium isostearate, barium isostearate, aluminum isostearate, zinc isostearate, nickel isostearate, sodium behenate, potassium behenate, magnesium behenate, behenine Calcium acid, Barium behenate, Aluminum behenate, Zinc behenate, Behe Nickel, sodium montanate, potassium montanate, magnesium montanate, calcium montanate, barium montanate, aluminum montanate, zinc montanate, nickel montanate, lithium montanate, sodium octylate, lithium octylate, octylic acid Magnesium, calcium octylate, barium octylate, aluminum octylate, thallium octylate, lead octylate, nickel octylate, beryllium octylate, sodium 12-hydroxystearate, lithium 12-hydroxystearate, magnesium 12-hydroxystearate , Calcium 12-hydroxystearate, barium 12-hydroxystearate, aluminum 12-hydroxystearate, 12-hydroxy Thallium stearate, lead 12-hydroxystearate, nickel 12-hydroxystearate, beryllium 12-hydroxystearate, sodium sebacate, lithium sebacate, magnesium sebacate, calcium sebacate, barium sebacate, aluminum sebacate, sebacin Thallium acid, lead sebacate, nickel sebacate, beryllium sebacate, sodium undecylate, lithium undecylate, magnesium undecylate, calcium undecylate, barium undecylate, aluminum undecylenate, thallium undecylate, lead undecylenate, nickel undecylenate , Beryllium undecylate, sodium ricinoleate, lithium ricinoleate, magnesium ricinoleate, ricino Calcium Le, barium ricinoleate, aluminum ricinoleate, ricinoleic acid thallium, ricinoleic lead, ricinoleic acid nickel, ricinoleic acid beryllium and the like. Among these, calcium stearate, calcium 12-hydroxystearate, calcium montanate, magnesium stearate, magnesium 12-hydroxystearate, magnesium montanate, zinc stearate, zinc 12-hydroxystearate and zinc montanate are preferably used. . Two or more fatty acid metal salts can be used in combination.

  Among these, from the viewpoint of better moldability, at least one selected from the group consisting of calcium stearate, magnesium stearate, calcium laurate, and calcium laurate is particularly preferable.

1.5. Other components The resin composition according to the present invention includes various additives such as lubricants, antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments, hydrolysis inhibitors, polycaprolactone, and polyamides. , Synthetic resin such as polyvinyl alcohol and cellulose ester, animal / plant material fine powder such as starch, cellulose, paper, wood powder, chitin / chitosan, coconut shell powder, walnut shell powder, or a mixture of these It may be included as a “component”. These can be arbitrarily used as long as the effects of the present invention are not impaired. These may be used alone or in combination of two or more. The additive amount of these additives is usually such that the total amount of compounds to be mixed is 0.01% by weight or more and 40% by weight or less with respect to the total amount of the resin composition so as not to impair the physical properties of the resin composition. It is preferable to make it.

1.5.1. Lubricant For example, when a lubricant is included in the resin composition according to the present invention, the moldability of the resin composition can be improved.

  As the lubricant, known ones can be used without any particular limitation. Specifically, paraffins such as paraffin oil and solid paraffin, higher fatty acids such as stearic acid and palmitic acid, higher alcohols such as palmityl alcohol and stearyl alcohol, calcium stearate, zinc stearate, barium stearate, aluminum stearate, Metal salts of fatty acids such as magnesium stearate and sodium palmitate, fatty acid esters such as butyl stearate, glycerin monostearate and diethylene glycol monostearate, stearamide, methylene bisstearamide, ethylene bisstearamide, oxystearic acid Waxes such as fatty acid amides such as ethylenediamide, methylolamide, oleylamide, stearic acid amide, erucic acid amide, carnauba wax, montan wax, etc. Kind and the like. In addition, a lubricant and wax may be used individually by 1 type, and may be used 2 or more types by arbitrary ratios and combinations. Of these, erucic acid amide is particularly preferred. The content of these lubricants is usually 0.01 to 2% by weight in the resin composition, preferably 0.05 to 0.5% by weight.

1.5.2. Antistatic Agent An antistatic agent can also be included in the resin composition according to the present invention. Any antistatic agent can be used as long as the effects of the present invention are not significantly impaired. As a specific example, a surfactant type nonionic, cationic or anionic type is preferable.

  Nonionic antistatic agents include glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyldiethanolamine, hydroxyalkyl monoethanolamine, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester alkyldiethanol Amides and the like are listed. Of these, alkyldiethanolamines are preferred.

  Examples of the cationic antistatic agent include tetraalkylammonium salts and trialkylbenzylammonium salts.

  Examples of the anionic antistatic agent include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates. Of these, alkylbenzene sulfonate is preferable. This is because the kneadability with the resin is good and the antistatic effect is high.

  The amount of the antistatic agent used is arbitrary as long as the effects of the present invention are not significantly impaired. % By weight or less, more preferably 3% by weight or less. If it exceeds the above range, the surface stickiness of the resin composition further occurs, and the product value tends to decrease. On the other hand, if it is below the above range, the effect of improving the antistatic property tends to be reduced.

1.5.3. Other Additives In addition to the additives described above, the resin composition of the present invention may contain starch, a light-resistant agent, an ultraviolet absorber, a heat stabilizer, a terminal blocking agent, and the like.

  Specific examples of starch include corn starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, pea starch, etc., both of which are unmodified and modified products. it can. Modification includes all modification methods such as chemical, physical, and biological, and chemical modification includes esterification, etherification, oxidation, reduction, or partial or all of the structural units of carbohydrates (polysaccharides). It shows that it is modified by a chemical reaction such as coupling, dehydration, hydrolysis, dehydrogenation, halogenation, etc., and particularly shows that a hydroxyl group is etherified or esterified. Physical modification means changing physical properties such as changing the crystallinity. Biological degeneration refers to changing a chemical structure or the like using a living organism.

  Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester decaneate, a reaction product of 1,1-dimethylethyl hydroperoxide and octane, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (1,2,2 , 6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate , 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-tert-butyl) -4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, poly [[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine -2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] And hindered amine stabilizers. The light stabilizer is preferably used in combination with an ultraviolet absorber, and a combination of a hindered amine stabilizer and an ultraviolet absorber is effective.

  The amount of the light proofing agent to be mixed is preferably 100 ppm or more, more preferably 200 ppm or more, and preferably 5 parts by weight or less, more preferably 1 part by weight or less, and still more preferably based on the weight of the resin composition. Is 0.5 parts by weight or less. Below this range, the effect of the light resisting agent tends to be small. Moreover, when it exceeds this range, the manufacturing cost tends to increase, and the heat resistance of the resin composition tends to be inferior, or the light-proofing agent tends to bleed out.

  As the ultraviolet absorber, 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol, 2- (4,6-diphenyl-1,3,5) -Triazin-2-yl) -5-[(hexyl) oxy] phenol and the like. As the ultraviolet absorber, it is particularly preferable to use two or more different types of ultraviolet absorbers in combination.

  The amount of the ultraviolet absorber to be mixed is arbitrary as long as the effect of the present invention is not significantly impaired, but is preferably 100 ppm or more, more preferably 200 ppm or more, and preferably 5% by weight with respect to the resin composition. % Or less, more preferably 2% by weight or less, still more preferably 0.5% by weight or less. Below this range, the effect of the ultraviolet absorber tends to decrease. Moreover, when it exceeds this range, the production cost tends to be too high, the heat resistance of the resin composition is inferior, or the ultraviolet absorber bleeds out.

  Examples of the heat stabilizer include dibutylhydroxytoluene (BHT; 2,6-di-t-butyl-4-methylphenol), 2,2′-methylenebis (4-methyl-6-t-butylphenol), pentaerythritol tetrakis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″ -(Mesitylene-2,4,6-triyl) tri-p-cresol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [(4 -Tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-to (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [[3,5- Bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, bis (2,2′-dihydroxy-3,3′-di-tert-butyl-5,5′-dimethylphenyl) ethane, N , N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide and other hindered phenol thermal stabilizers; tridecyl phosphite, diphenyl decyl phosphite , Tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite, bis [2,4- (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid stabilizers such as phosphorous acid, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite; 3-hydroxy Lactone-based thermal stabilizers such as -5,7-di-tert-butyl-furan-2-one and xylene reactive organisms; sulfur-based antioxidants such as dilauryl thiodipropionate and distearyl thiodipropionate And so on.

  The amount of the heat stabilizer to be mixed is preferably 100 ppm or more, more preferably 200 ppm or more, and preferably 5 parts by weight or less, more preferably 1 part by weight or less, based on the weight of the resin composition. Preferably it is 0.5 weight part or less. Below this range, the effect of the heat stabilizer tends to be small. On the other hand, if it exceeds this range, the manufacturing cost tends to be high, and the bleedout of the thermal stabilizer may occur.

  The end-capping agent is mainly used for the purpose of suppressing hydrolysis due to moisture in the atmosphere, and includes carbodiimide compounds, epoxy compounds, oxazoline compounds, etc. Among the above carbodiimide compounds, as monocarbodiimide compounds, , Dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, and the like. Of these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferred because they are easily available industrially.

  Examples of the polycarbodiimide compound include U.S. Pat. No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Pat. Org. Chem. 28, p2069-2075 (1963), and Chemical Review 1981, 81, No. 4, p. What was manufactured by the method described in 619-621 grade | etc., Can be used.

  Examples of the organic diisocyanate that is a raw material for producing a polycarbodiimide compound include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and mixtures thereof. Specifically, 1,5-naphthalene diisocyanate, 4, 4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4- A mixture of tolylene diisocyanate and 2,6-tolylene diisocyanate, hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate , Dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexane diisocyanate, tetramethylxylylene diisocyanate, 2,6-diisopropylphenyl isocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, etc. Can do.

As the carbodiimidization catalyst used in the decarboxylation condensation reaction of organic diisocyanate, organophosphorus compounds and organometallic compounds represented by the general formula M (OR) _n (where M is titanium, sodium, potassium, vanadium, tungsten, hafnium) , Zirconium, lead, manganese, nickel, calcium, barium or the like, R represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n can be a metal atom M Is preferred). Among them, phospholene oxides are preferable for organic phosphorus compounds, and alcosides of titanium, hafnium, or zirconium are preferable for organometallic compounds.

  Specific examples of the phospholene oxides include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, and 1,3-dimethyl-2. -Phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1-oxide and their double bond isomers Can be illustrated. Of these, 3-methyl-1-phenyl-2-phospholene-1-oxide, which is easily available industrially, is particularly preferable.

  When synthesizing these polycarbodiimide compounds, a desired degree of polymerization can be controlled by using an active hydrogen-containing compound capable of reacting with monoisocyanate or other terminal isocyanate groups. Compounds used for such purposes include monoisocyanate compounds such as phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, naphthyl isocyanate, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, Hydroxyl group-containing compounds such as polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether, amino group-containing compounds such as diethylamine, dicyclohexylamine, β-naphthylamine and cyclohexylamine, carboxyl group-containing compounds such as succinic acid, benzoic acid and cyclohexane acid, ethyl mercaptan , Mercapto group-containing compounds such as allyl mercaptan and thiophenol, And it can be exemplified various epoxy group-containing compound.

  These carbodiimide compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them. In the present invention, it is particularly preferable to use a polycarbodiimide compound, and the degree of polymerization thereof is preferably 2 or more, more preferably 4 or more, and the upper limit is preferably 40 or less, more preferably 20 or less. . The amount of carbodiimide used is preferably 0.1 to 5% by weight based on the entire resin composition.

  In addition to these, known surface wettability improvers, flame retardants, mold release agents, incineration aids, pigments, dispersion aids, surfactants, hydrolysis inhibitors, crystal nucleating agents, compatibilizing agents and the like are included. Also good.

2. Production Method of Resin Composition A known method can be applied as a production method of the resin composition according to the present invention. For example, blended aliphatic polyester resin (A), inorganic filler (B), plasticizer (C), (and fatty acid metal salt (D)) is fed to an extruder and melt-kneaded; aliphatic polyester A method of individually supplying an epoxy resin (A), an inorganic filler (B), a plasticizer (C) (and a fatty acid metal salt (D)) to an extruder and melt-kneading; a blended aliphatic polyester resin (A ), A method in which the plasticizer (C) (and fatty acid metal salt (D)) is supplied to an extruder and melt-kneaded, and the inorganic filler (B) is supplied to the side and melt-kneaded; an aliphatic polyester type Resin (A), inorganic filler (B), plasticizer (C) (and fatty acid metal salt (D)) are individually fed to the extruder and melt-kneaded, and the inorganic filler (B) is side-faced. Examples thereof include a method of supplying and melt-kneading. From the viewpoint of productivity, an inorganic filler (B) is provided where the blended aliphatic polyester resin (A), plasticizer (C) (and fatty acid metal salt (D)) are supplied to an extruder and melt-kneaded. ) Is preferably supplied to the side and melt kneaded.

3. Molded product The method for obtaining a molded product from the resin composition of the present invention is not particularly limited, and various molding methods usually employed for thermoplastic resins can be applied, such as injection molding, injection blow molding, Injection molding methods such as injection compression molding and foam molding; pipe / tube, odd-shaped products, wire coating, T-die film / sheet, inflation film, laminating, monofilament extrusion molding methods; blow molding method, vacuum molding method, A calendar molding method, a compression molding method, etc. can be mentioned.

4). Spherical molded product The resin molded product of the present invention is more preferably a spherical molded product in order to more effectively utilize the effects of high specific gravity, excellent moldability, and appropriate biodegradability. Since the resin composition according to the present invention is excellent in moldability and can eliminate the mixing of bubbles during molding, there is no unevenness in the density of the molded product. Therefore, it can be particularly preferably used for applications requiring high specific gravity and density uniformity. For example, when the specific gravity of the resin composition is 1.5 to 3.0, the resin composition can be suitably used as a plastic bullet for shooting competition, an OA device, or a housing for home appliances. Since the resin composition according to the present invention has moderate biodegradability and has a reduced impact on the environment, for example, in the case of a plastic bullet, there is no need to collect bullets released outdoors. .

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.

<Evaluation of physical properties>
-Measurement of MFR value Based on JIS K7210, the MFR value was measured at 190 degreeC and the load of 2.16kg using the melt indexer.

・ Measurement of ¹ H-NMR
^In the measurement of ¹ H-NMR, about 30 mg of a sample was weighed into an NMR sample tube having an outer diameter of 5 mm, dissolved in 0.75 mL of deuterated chloroform, and then dissolved in ¹ H-NMR at room temperature using a Bruker AVANCE400 spectrometer. The spectrum was measured. The standard of chemical shift was tetramethylsilane (TMS) of 0.00 ppm.

-Melting point measurement The melting point was measured by using a differential scanning calorimeter manufactured by PerkinElmer Co., Ltd., product name: DSC7, and 10 mg sample was heated and melted in a nitrogen stream at a flow rate of 50 mL / min, and then 10 ° C / min. After cooling at a rate of 1, the melting peak temperature at the time of heating at a rate of 10 ° C./min was used.

[Manufacture of aliphatic polyester resins]
(Production Example 1)
In a reaction vessel equipped with a stirrer, a nitrogen inlet, a heating device, a thermometer and a vacuum outlet, 100 parts by weight of succinic acid, 99.2 parts by weight of 1,4-butanediol, and 0.24 part by weight of malic acid are used as raw materials. In addition, 7.0 parts by weight of 90% DL lactic acid aqueous solution in which 1% by weight of germanium oxide was dissolved in advance was charged. Nitrogen gas was introduced while stirring the contents of the container, the reaction was started from 120 ° C. under a nitrogen gas atmosphere, and the temperature was raised to 200 ° C. over 1 hour and 40 minutes. Subsequently, the temperature was raised to 230 ° C. over 1 hour and 25 minutes, and at the same time, the pressure was reduced to 1 mmHg (133 Pa), and polymerization was performed at 230 ° C. and 1 mmHg (133 Pa) for 3 hours to obtain an aliphatic polyester resin. Hereinafter, this aliphatic polyester resin may be referred to as “resin 1”.

  The resulting aliphatic polyester resin had a melting point of 114 ° C., an MFR value of 50 g / 10 min, and the succinic acid unit in all aliphatic dicarboxylic acid units constituting the aliphatic polyester resin was 100 mol%. It was. Moreover, the specific gravity of the obtained aliphatic polyester resin itself was 1.26.

Examples 1-6, Comparative Examples 1-4
“Talc PKP-53S” shown below, which corresponds to the resin 1 produced in Production Example 1 and the inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5, the specific gravity of 3.5 or more and 5. “Beautiful barium sulfate BD” shown below corresponding to inorganic filler (B-2) of less than 0, glycerin corresponding to plasticizer (C), calcium stearate corresponding to fatty acid metal salt (D), hindered phenol “Irganox 1010” shown below, which corresponds to a heat stabilizer, is mixed so as to have the content ratio shown in Table 1 below, and kneaded at a set temperature of 200 ° C. with a twin-screw kneader (PCM30 manufactured by Ikegai Steel Corporation). Resin pellets were obtained. The resin pellets were molded according to ISO 294-1 using an injection molding machine (IS100EN manufactured by Toshiba Machine Co., Ltd.) set at a cylinder temperature of 180 ° C. and a mold temperature of 40 ° C. to prepare test pieces.
“Talc PKP-53S”: talc, manufactured by Fuji Talc Kogyo Co., Ltd. “fertile barium sulfate BD”: barium sulfate, manufactured by Sakai Chemical Industry Co., Ltd. “Irganox 1010”: hindered phenol-based heat stabilizer, manufactured by BASF

  The following evaluation was performed about the obtained resin pellet and the test piece.

<Moldability>
When the test piece was molded, the moldability was evaluated according to the following criteria by visual observation.
◯: Less than 1 sample was found to have bubbles, burrs, sink marks, etc. per 10 test pieces.
Δ: The number of bubbles, burrs, sink marks, etc. generated per 10 test pieces was 1 or more and less than 2.
X: The number of bubbles and burrs generated per 10 test pieces was 2 or more.
What passed more than (triangle | delta) was set as the pass.

<Specific gravity>
Using the molded test piece, the specific gravity was measured according to JIS K7112 A method (underwater substitution method).

<Biodegradability>
A resin pellet was press-molded at 180 ° C. to prepare a film having a thickness of 100 μm, and a “test piece type 2” test piece described in JIS K7127 was punched with a punching blade, and the water content was adjusted to 20% by weight. The film was buried in the soil of the Yokkaichi Office of Mitsubishi Chemical Corporation. The temperature condition of the biodegradation test is 40 ° C., the embedment period is 7, 14, 21, and 28 days. The film is taken out from the soil and the appearance is observed. Evaluated. A case where Δ appears between 7 and 28 days was regarded as acceptable.
○: There was no change in the appearance of the film.
Δ: There were changes such as cracks and pores in the appearance of the film.
X: The film changed so much that the original shape was not retained.

  The evaluation results are shown in Table 1 below.

  As is clear from the results shown in Table 1, all of the resin compositions according to Examples 1 to 6 had high specific gravity, excellent moldability, and moderate biodegradability. On the other hand, the resin composition according to Comparative Example 1 with a small amount of the inorganic filler (B) was not able to have a high specific gravity, and was further judged to be too biodegradable. Moreover, since the quantity of the inorganic filler (B) was too much, the resin composition according to Comparative Example 2 could not be molded even when the plasticizer (C) was added. Furthermore, the resin compositions according to Comparative Examples 3 and 4 could not be molded because the amount of the plasticizer (C) was too large.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. In addition, the resin composition with such a change and a molded article formed by molding the resin composition can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. It should be understood as being included within the scope of the present invention.

  The resin composition according to the present invention has high specific gravity and excellent moldability, and has appropriate biodegradability. In other words, it is used as a molded product that has a strong and sufficient mass at the beginning of use and can be properly biodegraded after use, such as a plastic bullet for shooting competitions, a container or case for immersion in water, etc. be able to.

Claims (8)

In the resin composition containing the aliphatic polyester resin (A), the inorganic filler (B) and the plasticizer (C),
The specific gravity of the inorganic filler (B) is 2.5 or more,
The plasticizer (C) is one or more plasticizers selected from the group consisting of glycerin, sorbitol, pentaerythritol, propylene glycol and ethylene glycol;
50 to 550 parts by weight of the inorganic filler (B) and 0.01 to 20 parts by weight of the plasticizer (C) are contained with respect to 100 parts by weight of the aliphatic polyester resin (A). Resin composition.   The resin composition according to claim 1, further comprising 0.01 to 10 parts by weight of a fatty acid metal salt (D) with respect to 100 parts by weight of the aliphatic polyester resin (A).   The inorganic filler (B) is composed of an inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 and an inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0. The resin composition according to claim 1, wherein the resin composition is a mixture.   The inorganic filler (B-1) having a specific gravity of 2.5 or more and less than 3.5 is at least one selected from the group consisting of talc, mica, calcium carbonate, aluminum hydroxide, calcium hydroxide, and magnesium hydroxide. The inorganic filler (B-2) having a specific gravity of 3.5 or more and less than 5.0 is at least one selected from the group consisting of barium sulfate, barium carbonate, and titanium oxide. Item 4. The resin composition according to Item 3.   The resin composition according to any one of claims 2 to 4, wherein the fatty acid metal salt (D) is at least one selected from the group consisting of calcium stearate, magnesium stearate, and calcium laurate.   The said aliphatic polyester-type resin (A) contains an aliphatic diol unit and an aliphatic dicarboxylic acid unit, The resin composition in any one of Claims 1-5 characterized by the above-mentioned.   The molded article obtained by shape | molding the resin composition in any one of Claims 1-6.   The spherical molded product obtained by shape | molding the resin composition in any one of Claims 1-6.