JP2003253106A - Resin composition and molded product made of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition which is excellent in a crystallization property and heat resistance, and a molded product made of the same. <P>SOLUTION: The resin composition contains a (A) polylactic acid resin and a (B) polyacetal resin. The polylactic acid resin comprises the same resin (A-1) containing the both of a poly L-lactic acid resin having an L-lactic unit as a main component and a poly D-lactic acid resin having a D-lactic acid unit as a main component and/or a (A-2) block copolymer consisting of a poly L- lactic acid segment having an L-lactic acid unit as a main component and a poly D-lactic acid segment having a D-lactic acid as a main component. The molded product is made of the resin composition. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition having excellent crystallization characteristics and heat resistance, and a molded article made of this resin composition.

[0002]

2. Description of the Related Art Polylactic acid resin is expected to be a practically excellent biodegradable polymer because it has a high melting point among the biodegradable polymers and can be melt-molded. However, since the polylactic acid resin has a slow crystallization rate, there is a limit in crystallizing it and using it as a molded article. For example, when polylactic acid resin is injection molded, long molding cycle time and heat treatment after molding are required,
In addition, there was a large practical problem such as a large deformation during molding and heat treatment. In addition, since the melting point is low, the use thereof at high temperature is limited, so that its use is limited.

On the other hand, polyacetal resins are widely used as injection-molded products because of their excellent balance of mechanical properties and moldability, but further improvement in heat resistance is required.

The technique of blending two or more polymers is widely known as a polymer alloy, and this polymer alloy is widely used for the purpose of improving the defects of individual polymers. However,
When two or more kinds of polymers are mixed, most of them have poor dispersibility between the polymers and cannot be processed into pellets or molded articles, or tend to exhibit inferior properties.

In rare cases, however, the two polymers may form a uniform amorphous phase, which is generally known as a compatible or miscible polymer alloy and has excellent properties. It is expected to be shown, but there are few examples.

A polymer compatible with the polylactic acid resin is polyethylene glycol (for example, Polymer).
r 37 (26), 5849-5857 (1996)).
Or polymethylmethacrylate (for example, Polyme
r 39 (26), 6891-6897 (1998)).
However, when these polymers are mixed, there is a problem in that the strength and crystallinity of the polylactic acid resin are significantly reduced.

Further, as a polymer compatible with the polyacetal resin, polyvinylphenol (for example, P
polymer 33 (4), 760-766 (199).
Although 2)) is known, this polyvinylphenol has a problem that the physical properties of the resin after mixing are deteriorated because the molecular weight is generally low.

[0008]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying the solution of the above-mentioned problems in the prior art.

Therefore, it is an object of the present invention to provide a resin composition having excellent crystallization characteristics and heat resistance, and a molded article made of the resin composition.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, a resin composition containing a polylactic acid resin and a polyacetal resin, wherein the polylactic acid resin is A poly-L-lactic acid segment containing both L-lactic acid unit as a main component and a poly-D-lactic acid resin having a D-lactic acid unit as a main component, or a poly-L-lactic acid segment containing an L-lactic acid unit as a main component and D The present invention has been completed by discovering that a resin composition which is a block copolymer composed of a poly-D-lactic acid segment containing a lactic acid unit as a main component has excellent properties.

That is, the present invention is a resin composition containing (A) a polylactic acid resin and (B) a polyacetal resin, wherein the polylactic acid resin contains (A-1) L-lactic acid unit as a main component. A poly (lactic acid) resin containing both a poly (L-lactic acid) resin and a poly (D-lactic acid) resin having a D-lactic acid unit as a main component, and / or (A-2) a poly (L-lactic acid) segment having an L-lactic acid unit as a main component and D -A resin composition which is a block copolymer comprising a poly-D-lactic acid segment containing a lactic acid unit as a main component.

In the resin composition of the present invention,
When the total amount of the (A) polylactic acid resin and the (B) polyacetal resin is 100 parts by weight, the compounding amount of the (A) polylactic acid resin is 99 parts by weight or less and 50 parts by weight or more,
When the total amount of the (A) polylactic acid resin and the (B) polyacetal resin is 100 parts by weight, the compounding amount of the (B) polyacetal resin is 99 parts by weight or more and more than 50 parts by weight, A) polylactic acid resin and (B) polyacetal resin are compatibilized, and (A) polylactic acid resin has a ratio of (A-1) poly L lactic acid resin to poly D lactic acid resin of 95: 5 to 5 : 95 or (A-2)
The ratio of the amount of poly (L-lactic acid) segment to poly (D-lactic acid) segment in the block copolymer is 95: 5 to 5:95, and (A) polylactic acid resin (A-1) L-lactic acid unit is 80 mol% or more. A poly (L-lactic acid) resin having both a poly (L-lactic acid) resin and a poly (D-lactic acid) resin having D-lactic acid unit of 80 mol% or more, or (A-2) In the polylactic acid resin (A-1), which is a block copolymer composed of a poly D lactic acid segment having 80 mol% or more of lactic acid units,
Regarding the weight average molecular weight Mw (L) of the poly L lactic acid resin and the weight average molecular weight Mw (D) of the poly D lactic acid resin, Mw
(L) / Mw (D) or Mw (D) / Mw (L), whichever is larger, is 2 or more, (A) the polylactic acid resin has a melting point of 190 ° C. or more, (B) ) A preferable condition is that the polyacetal resin is a polyacetal copolymer and further contains a crystallization accelerator. When these conditions are applied, it is possible to expect to obtain a more excellent effect.

The molded article of the present invention is characterized by comprising the above resin composition.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The polylactic acid resin (A) used in the present invention is poly (L) containing (A-1) L-lactic acid unit as a main component.
A polylactic acid resin containing both a lactic acid resin and a poly-D-lactic acid resin having a D-lactic acid unit as a main component, and (A-2) a poly-L-lactic acid segment having an L-lactic acid unit as a main component and a D-lactic acid unit as a main component. A block copolymer comprising a poly D lactic acid segment as a component, wherein the (A) polylactic acid resin is a polylactic acid resin (A-1) and a polylactic acid block copolymer (A-2).
May be included at the same time.

The polylactic acid used in the present invention may contain a copolymerization component other than lactic acid. The copolymerization component may be contained in both the poly L lactic acid resin or segment and the poly D lactic acid resin or segment, or may be contained in only one of them. Other copolymerizable components include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, Pentaerythritol,
Bisphenol A, glycol compounds such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid,
Glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5 Dicarboxylic acids such as tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxycarboxylic acids such as hydroxybenzoic acid, and caprolactone, valerolactone, propiolactone,
Lactones such as undecalactone and 1,5-oxepan-2-one can be mentioned. The copolymerization ratio of these other copolymerization components is such that the effects of the present invention are not impaired, and is preferably 20 mol% or less, and more preferably 10 mol% or less, based on all monomers.

The component (A-1) in the present invention is a polylactic acid resin containing both a poly-L-lactic acid resin containing L-lactic acid units as a main component and a poly-D-lactic acid resin containing D-lactic acid units as a main component. is there. The poly-L-lactic acid resin containing L-lactic acid units as a main component preferably contains 80% or more of L-lactic acid units, more preferably 90% or more, and 95% or more. Is more preferable. The poly-D-lactic acid resin containing D-lactic acid units as the main component preferably contains 80% or more of D-lactic acid units, and more preferably 90% or more.
It is more preferable to contain 5% or more.

In the present invention, poly L lactic acid resin and poly D are used.
The weight ratio of the lactic acid resin is not particularly limited,
It is preferably 95: 5 to 5:95 and preferably 90:10.
10:90 is more preferable, and 70: 30-
30:70 is more preferable, and 60: 40-
40:60 is particularly preferred.

The polylactic acid resin (A
-1), poly-L containing L-lactic acid unit as a main component
Among the lactic acid resin and the poly-D-lactic acid resin containing D-lactic acid unit as a main component, at least one has a weight average molecular weight of preferably 300,000 or less, more preferably 150,000 or less, and further preferably 100,000 or less. More preferably. The weight average molecular weights of both the poly (L-lactic acid) resin containing L-lactic acid units as the main component and the poly (D-lactic acid) resin containing D-lactic acid units as the main component are preferably 10,000 or more and 30,000 or more. Is more preferable.

The polylactic acid resin (A used in the present invention
-1), poly-L containing L-lactic acid unit as a main component
Weight average molecular weight Mw (L) of lactic acid resin and weight average molecular weight Mw of poly D lactic acid resin containing D-lactic acid unit as a main component
For (D), Mw (L) / Mw (D) or Mw
The larger value of (D) / Mw (L) is preferably 2 or more, more preferably 3 or more, and further preferably 4 or more.

The mixture of the above-mentioned preferable poly-L-lactic acid resin and poly-D-lactic acid resin in the component (A-1) easily forms a stereocomplex, but in the present invention, the poly-lactic acid resin having such a combination is used. By blending a lactic acid resin with a polyacetal resin, excellent crystallization characteristics can be achieved.

In the present invention, polylactic acid resin (A-1)
The melting temperature of is preferably 190 ° C or higher, more preferably 200
C. or higher is preferable, and 210.degree. C. or higher is particularly preferable. The polylactic acid resin here refers to the melting point of a mixture of poly L lactic acid resin and poly D lactic acid resin. Polylactic acid resin is
In particular, in the above preferred embodiment, a stereo complex can be easily formed, and in this case, the melting temperature can be set to 190 ° C. or higher. Can be higher.

As the method for producing the poly (L-lactic acid) resin and the poly (D-lactic acid) resin (A), a known polymerization method can be used. Examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide. be able to.

The component (A-2) in the present invention is a block copolymer comprising a poly-L-lactic acid segment containing an L-lactic acid unit as a main component and a poly-D-lactic acid segment containing a D-lactic acid unit as a main component.

In the above block copolymer, the poly-L-lactic acid resin or segment containing L-lactic acid units as a main component preferably contains 80% or more, and further 90% or more, of L-lactic acid units. It is preferable to contain 95% or more, and it is more preferable to contain 95% or more. D-
The poly-D-lactic acid resin or segment containing a lactic acid unit as a main component preferably contains 80% or more of D-lactic acid unit, more preferably 90% or more, and 95% or more. Is more preferable.

The weight ratio of the poly (L-lactic acid) segment to the poly (D-lactic acid) segment in the block copolymer is not particularly limited, but is preferably 95: 5 to 5:95, preferably 90:10 to 10 :. 90 is more preferable, 70:30 to 30:70 is further preferable, and 60:40 to 40:60 is particularly preferable.

The weight average molecular weight of the block copolymer is not particularly limited, but is preferably 100,000 or more, more preferably 100,000 or more and 1,200,000 or less, further 120,000 or more 50. It is preferably 10,000 or less.

In the polylactic acid block copolymer (A-2) used in the present invention, the minimum weight average molecular weight of one unit of the block copolymer is more preferably 5000 or more.

The above-mentioned preferred block copolymer is one that easily forms a stereo complex, and by blending such a block copolymer with a polyacetal resin, excellent crystallization characteristics can be achieved.

In the present invention, the weight average molecular weight means gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.
It is the value of the weight average molecular weight in terms of standard polymethylmethacrylate measured.

In the present invention, polylactic acid resin (A-2)
The melting temperature of is preferably 190 ° C or higher, more preferably 200
C. or higher is preferable, and 210.degree. C. or higher is particularly preferable. The polylactic acid resin here refers to the melting point of the block copolymer resin. The polylactic acid resin can easily form a stereocomplex in the above-mentioned preferred embodiment, and in this case, the melting temperature can be 190 ° C. or higher, and when other copolymerization components are small, , The melting temperature can be higher.

The polylactic acid block copolymer (A-2) can be produced by polymerizing the enantiomer monomer of the monomer unit of the segment in poly L lactic acid polymer or poly D lactic acid polymer. Polyfunctional lactic acid polymer and poly-D lactic acid polymer selected from polyvalent carboxylic anhydride, polyvalent carboxylic acid halide, polyvalent carboxylic acid, polyvalent isocyanate, polyvalent amine, polyhydric alcohol, and polyvalent epoxy compound And a method of binding with a volatile compound.

For example, poly L lactic acid polymer or poly D
In the method of polymerizing the enantiomer monomer of the monomer unit of the segment in the lactic acid polymer, the steps (1) and (2) below, the steps (1) to (3) below, or the following (1) to It is preferably produced by carrying out the step (4). (1) Using a compound containing two or more hydroxyl groups or amino groups in the molecule as a polymerization initiator, L-lactic acid or D-
The first step for producing a polymer (I) composed of lactic acid units. (2) A second step of producing a polymer (II) in which a segment having an enantiomer unit of a monomer unit of the polymer (I) as a monomer unit is bonded to the polymer (I). (3) A third step of producing a polymer in which a segment having an enantiomer unit of a monomer unit of a segment bonded in the previous step as a monomer unit is bonded to the polymer obtained in the previous step. (4) A fourth step of repeating the steps of (3).

As a method for binding the poly L lactic acid polymer and the poly D lactic acid polymer with a polyfunctional compound,
For example, a method in which the poly-L-lactic acid polymer and the poly-D-lactic acid polymer are dry-blended with the polyfunctional compound and then melt-kneaded using an extruder is preferable.

In the production of each segment of polylactic acid, a known polymerization method can be used, and examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide.

The polyacetal resin (B) used in the present invention is a polymer having an oxymethylene unit as a main repeating unit, and may be a so-called polyacetal homopolymer obtained by a polymerization reaction using formaldehyde or trioxane as a main raw material. May be any of the so-called polyacetal copolymers mainly composed of oxymethylene units and containing 15% by weight or less of oxyalkylene units having 2 to 8 adjacent carbon atoms in the main chain, and other structural units. It may be a copolymer containing, that is, a block copolymer, a terpolymer, or a cross-linked polymer.
Although they can be used alone or in combination of two or more, a polyacetal copolymer is preferable from the viewpoint of thermal stability.

The method for producing the (B) polyacetal resin in the present invention is not particularly limited and can be produced by a known method. As an example of a typical method for producing a polyacetal homopolymer, high-purity formaldehyde is introduced into an organic solvent containing an organic amine, an organic or inorganic tin compound, or a basic polymerization catalyst such as a metal hydroxide. Polymerization, the polymer is separated by filtration, and then heated in acetic anhydride in the presence of sodium acetate to acetylate the polymer terminal, and the like.

As a typical method for producing a polyacetal copolymer, high-purity trioxane and a copolymerization component such as ethylene oxide and 1,3-dioxolane are introduced into an organic solvent such as cyclohexane, and diethyl trifluoride is added. After cationic polymerization using a Lewis acid catalyst such as an ether complex, the catalyst is deactivated and the end groups are stabilized, or a solvent is not used at all, and a self-cleaning stirrer is used. A method in which trioxane, a copolymerization component and a catalyst are introduced and bulk polymerization is carried out, and then unstable terminals are further decomposed and removed, and the like can be mentioned.

The viscosity of these polymers is not particularly limited as long as it can be used as a molding material.
Melt flow rate (MFR) by TMD1238 method
Can be measured and the MFR is preferably in the range of 1.0 to 50 g / 10 minutes, particularly preferably 1.5 to 35 g / 10 minutes.

Further, as the polyacetal resin (B), it is preferable to use a resin containing a heat stabilizer and a generated gas supplement in advance.

It should be noted that by promoting the decomposition of the polyacetal resin, the durability and compatibility of the composition are impaired.
For formaldehyde, which has a high possibility of having a strong influence on the characteristics of the composition itself, it is preferable to keep it at most less than 500 ppm, more preferably not more than 250 ppm, and further 100 ppm with respect to the resin composition at most. It is preferable to keep it below, and it is more preferable not to contain it.

The present invention is characterized in that a composition having excellent crystallization characteristics and heat resistance can be obtained, and the composition of (A) polylactic acid resin and (B) polyacetal resin is particularly effective. The characteristics are different. When the total amount of (A) polylactic acid resin and (B) polyacetal resin is 100 parts by weight, 99 parts by weight or less of the polylactic acid resin and 50 parts by weight or more, particularly 99 parts by weight or less of the polylactic acid resin and 60 parts by weight or more are blended. The resin composition thus obtained is useful in improving the characteristics of the polylactic acid resin, and this resin composition is particularly effective in improving the crystallization characteristics and heat resistance. In addition, this resin composition may be biodegradable by taking advantage of the characteristics of polylactic acid.

When the total amount of (A) polylactic acid resin and (B) polyacetal resin is 100 parts by weight,
Polyacetal resin 99 parts by weight or more and more than 50 parts by weight, particularly in a resin composition containing 99 parts by weight or less and 60 parts by weight or more of polyacetal resin, it is possible to improve the properties of the polyacetal resin, and particularly, the processability and Effective in improving heat resistance.

When the (A) polylactic acid resin and the (B) polyacetal resin are blended according to the above-mentioned embodiment, both are usually in a compatibilized state. "Compatibilization" as used herein is used to describe the formation of a mixture of polymers that forms a homogeneous phase within the amorphous phase at the molecular level. That is, if one or both of the formulations form both crystalline and amorphous phases, compatible means that the amorphous phases are mixed at the molecular level.

The determination of compatibility in a formulation can be done in several ways. The most common method for judging compatibility is the glass transition temperature.
In compatible formulations, the glass transition temperature varies from that of each alone and often exhibits a single glass transition temperature. As a method for measuring the glass transition temperature, either a method using a differential scanning calorimeter (DSC) or a method using a dynamic viscoelasticity test can be used.

However, since the polyacetal resin is highly crystalline, there is a problem that the glass transition temperature becomes unclear when the content of the polyacetal resin is large. In this case, the crystallization temperature of the polyacetal resin can be used to judge the compatibility. That is,
This is because when the polyacetal resin forms a compatible blend with a resin having a slower crystallization rate than itself, the crystallization rate of the polyacetal resin is lower than that of a single substance. Therefore, the decrease in the crystallization rate can be judged by the decrease in the crystallization temperature during the temperature decrease measured by DSC.

In the resin composition of the present invention, the crystallization temperature of the polyacetal resin in the resin composition when the temperature is lowered is lower than the crystallization temperature of the polyacetal resin alone. The preferred reduction in crystallization temperature depends on the composition.

When the total amount of the (A) polylactic acid resin and the (B) polyacetal resin is 100 parts by weight, 99 parts by weight or less of the polylactic acid resin and more than 60 parts by weight and 1 part by weight or more and less than 40 parts by weight of the polyacetal resin are blended. If you do, DS
The decrease in crystallization temperature with respect to the polyacetal resin alone measured by C at a temperature lowering rate of 20 ° C./min is usually 5 ° C. or higher, and in a preferred embodiment, 7 ° C. or higher. The total of (A) polylactic acid resin and (B) polyacetal resin is 100
When 60 to 40 parts by weight of the polylactic acid resin and 40 to 60 parts by weight of the polyacetal resin are mixed in parts by weight, the decrease in the crystallization temperature with respect to the polyacetal resin alone is usually 2 ° C. or higher, and in a preferred embodiment, 4 ° C
That is all. When the total amount of (A) polylactic acid resin and (B) polyacetal resin is 100 parts by weight, when less than 40 parts by weight of polylactic acid resin and 1 part by weight or more and more than 60 parts by weight and 99 parts by weight or less of polyacetal resin are blended. The decrease in crystallization temperature with respect to the polyacetal resin alone is usually 0.2 ° C. or higher, and in a preferred embodiment, it is 0.5 ° C.
That is all.

When a film is made from a compatible formulation, it is optically transparent, whereas a film made from an incompatible formulation is generally opaque. This method can also be used as a determination of compatibility. However, when both are crystalline resins, such as a blend of polylactic acid resin and polyacetal resin,
Even if it is compatible, it may become opaque due to crystallization of either one, and the fact that the film is opaque does not mean that it is incompatible,
In the present invention, when the content of polylactic acid is relatively large, it is effective for judging compatibility.

For example, in the resin composition of the present invention, in a region where the content of the polylactic acid resin is high, by quenching to 0 ° C., a substantially transparent film having a film thickness of 100 μm can be formed. Is 90 at a film thickness of 100 μm
It is possible to form a film having a light transmittance of at least%. Further, by quenching to a lower temperature, a substantially transparent film can be obtained even in a region where the content of polylactic acid is low.

The thus obtained substantially transparent film is characterized by excellent toughness and excellent post-processability such as stretching because of the large amount of compatibilized polymer. The same applies to other molded articles such as fibers.

In the present invention, it is preferable that a crystallization accelerator is further included. The crystallization accelerator can be selected from a wide variety of compounds, but a crystal nucleating agent that promotes the formation of crystal nuclei of a polymer or a plasticizer that softens the polymer to facilitate movement and promotes crystal growth is preferable. Can be used.

The amount of the crystallization accelerator used in the present invention is 30 parts by weight or less and 0.01 parts by weight or more when the total amount of (A) polylactic acid resin and (B) polyacetal resin is 100 parts by weight. The amount is preferably 20 parts by weight or less, and more preferably 0.05 parts by weight or more.

As the crystal nucleating agent used as the crystallization accelerator in the present invention, those generally used as polymer crystal nucleating agents can be used without particular limitation. Either can be used. Specific examples of the inorganic crystal nucleating agent include talc, kaolinite, montmorillonite, synthetic mica, clay,
Examples thereof include zeolite, silica, graphite, carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium sulfide, boron nitride, calcium carbonate, barium sulfate, aluminum oxide, neodymium oxide, and metal salts of phenylphosphonate. These inorganic crystal nucleating agents are preferably modified with an organic substance in order to enhance dispersibility in the composition.

Specific examples of the organic crystal nucleating agent include:
Sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, myristic acid Sodium, potassium myristate, calcium myristate, sodium octacosanate, calcium octacosanate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanate, calcium montanate, toluyl Sodium acid, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium Organic carboxylic acid metal salts such as dibenzoate, lithium dibenzoate, sodium β-naphthalate and sodium cyclohexanecarboxylate, sodium p-toluenesulfonate, organic sulfonates such as sodium sulfoisophthalate, stearic acid amide, ethylenebislauric acid Amides, palmitic acid amides, hydroxystearic acid amides, erucic acid amides, carboxylic acid amides such as trimesic acid tris (t-butylamide), low density polyethylene, high density polyethylene, polypropylene, polyisopropylene, polybutene, poly-4-methyl Polymers such as pentene, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, high melting point polylactic acid, ethylene-acrylic acid or methacrylic acid A sodium salt of a copolymer, a sodium salt or a potassium salt of a polymer having a carboxyl group such as a sodium salt of a styrene-maleic anhydride copolymer (so-called ionomer),
Benzylidene sorbitol and its derivatives, phosphorus compound metal salts such as sodium-2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate, and 2,2-methylbis (4,6-di-t-). Butylphenyl) sodium etc. can be mentioned.

As the crystal nucleating agent used in the present invention, among the above-exemplified ones, at least one selected from talc and metal salt of organic carboxylic acid is particularly preferable. The crystal nucleating agent used in the present invention may be a single type or a combination of two or more types.

The amount of the crystal nucleating agent is preferably 0.01 to 30 parts by weight based on 100 parts by weight of the total of (A) polylactic acid resin and (B) polyacetal resin.
The range of 0.05 to 10 parts by weight is more preferable,
A range of 5 parts by weight is more preferable.

As the plasticizer used in the present invention, those generally well known can be used, and examples thereof include polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers and phosphoric acid esters. Examples thereof include plasticizers, polyalkylene glycol plasticizers and epoxy plasticizers.

Specific examples of the polyester plasticizer include:
Acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, ethylene Examples thereof include polyesters composed of diol components such as glycol and diethylene glycol, polyesters composed of hydroxycarboxylic acid such as polycaprolactone, and the like. These polyesters may be end-capped with a monofunctional carboxylic acid or monofunctional alcohol, or may be end-capped with an epoxy compound or the like.

Specific examples of the glycerin plasticizer include glycerin monoacetomonolaurate, glycerin diacetomonolaurate, glycerin monoacetomonostearate, glycerin diacetomonooleate and glycerin monoacetomonomonate. .

Specific examples of the polycarboxylic acid ester plasticizer include phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate and butylbenzyl phthalate. Trimellitic acid esters such as tributyl trimellitate, trioctyl trimellitate and trihexyl trimellitate, diisodecyl adipate, sebacic acid esters such as n-octyl-n-decyl adipate adipate, triethyl acetylcitrate, acetyl Examples include citric acid esters such as tributyl citrate, azelaic acid esters such as di-2-ethylhexyl azelate, dibutyl sebacate, and sebacic acid esters such as di-2-ethylhexyl sebacate. Door can be.

Specific examples of the phosphate ester plasticizer include tributyl phosphate, tri-2-ethylhexyl phosphate, trioctyl phosphate, triphenyl phosphate, diphenyl-2-ethylhexyl phosphate and tricresyl phosphate. be able to.

Specific examples of the polyalkylene glycol type plasticizer include polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and / or random copolymer, polytetramethylene glycol, ethylene oxide addition polymer of bisphenols. , Propylene oxide addition polymers of bisphenols, polyalkylene glycols such as bisphenol tetrahydrofuran addition polymers or their terminal epoxy modified compounds, terminal ester modified compounds, and terminal blocking compounds such as terminal ether modified compounds. .

The epoxy plasticizer generally refers to an epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil, etc. In addition to the above, a so-called main ingredient of bisphenol A and epichlorohydrin is used. Epoxy resins can also be used.

Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate, and fatty acid amides such as stearic acid amide. Examples thereof include aliphatic carboxylic acid esters such as butyl oleate, methyl acetylricinoleate, oxyacid esters such as butyl acetylricinoleate, pentaerythritol, various sorbitols, polyacrylic acid esters, silicone oils, and paraffins. .

Among the above-exemplified plasticizers, at least one selected from polyester plasticizers and polyalkylene glycol plasticizers is particularly preferable as the plasticizer used in the present invention. The plasticizer used in the present invention is
Only one kind may be used, or two or more kinds may be used in combination.

The amount of the plasticizer blended is preferably in the range of 0.01 to 30 parts by weight with respect to 100 parts by weight of the total of the (A) polylactic acid resin and the (B) polyacetal resin, and is preferably 0.
The range of 1 to 20 parts by weight is more preferable, and the range of 0.5 to 10 parts by weight is further preferable.

With respect to the resin composition of the present invention, a reinforcing material (glass fiber, carbon fiber,
Metal fibers, natural fibers, organic fibers, glass flakes, glass beads, ceramic fibers, ceramic beads, asbestos, wollastonite, talc, clay, mica (natural and synthetic), sericite, zeolite, bentonite, montmorillonite, dolomite, kaolin, Finely powdered silicic acid, feldspar powder, potassium titanate, shirasu balloon, calcium carbonate, magnesium carbonate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide,
Aluminum silicate, silicon oxide, gypsum, novaculite, dawsonite or clay etc.), stabilizers (hindered phenol, hydroquinone, phosphites and their substitution products, resorcinol, salicylate, benzotriazole, benzophenone, etc.), lubricants, mold release Agents (Montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide, polyethylene wax, etc.), dyes (nigrosin, etc.)
And colorants containing pigments (cadmium sulfide, phthalocyanine, etc.), anti-coloring agents (phosphite, hypophosphite, etc.), flame retardants (red phosphorus, phosphoric acid ester, brominated polystyrene, brominated polyphenylene ether, bromine) Polycarbonate, magnesium hydroxide, melamine and cyanuric acid or salts thereof, conductive agents or colorants (carbon black etc.), slidability improvers (graphite,
Fluorine resin, etc.), and one or more kinds of antistatic agents and the like can be added.

With respect to the resin composition of the present invention, other thermoplastic resins (for example, polyolefins such as polyethylene and polypropylene, polyamides, acrylic resins, polyphenylene sulfide resins, polyethers, etc.) may be used as long as the object of the present invention is not impaired. Ether ketone resin, polyester, polysulfone, polyphenylene oxide, polyimide, polyetherimide, etc. and thermosetting resin (eg phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin etc.) and soft thermoplastic resin (eg ethylene / Glycidyl methacrylate copolymer, ethylene / propylene terpolymer,
At least one kind of soft polyolefin polymer such as ethylene / butene-1 copolymer, various core-shell type elastomers, polyester elastomer, polyamide elastomer, etc.) can be further added.

The method for producing the resin composition of the present invention is not particularly limited, but for example, after pre-blending a polylactic acid resin, a polyacetal resin and, if necessary, other additives, uniaxially at or above the melting point. Alternatively, a method of uniformly melt-kneading with a twin-screw extruder or a method of removing the solvent after mixing in a solution is preferably used.

The resin composition of the present invention is a composition having unique properties, and can be processed into various molded products by a method such as injection molding or extrusion molding and used.

The molded articles made of the resin composition of the present invention include injection molded articles, extrusion molded articles, blow molded articles, and the like. Sheets, films, bottles, fibers,
It is also useful as a cloth, a non-woven fabric, a composite material with other materials, and the like. Further, these molded articles can be used for various purposes such as construction civil engineering materials, agricultural materials, horticultural materials, electric / electronic parts, automobile parts, medical materials, clothing and daily necessities.

[0073]

The present invention will now be described in more detail by way of examples, which should not be construed as limiting the present invention.

[Examples 1 to 6 and Comparative Examples 1 to 7] The content of D-form was 2% and the weight average of PMMA conversion by gel permeation chromatography (GPC) measurement using hexafluoroisopropanol as a solvent. Poly L lactic acid resin having a molecular weight of the value shown in Table 1, poly L lactic acid resin having an L-form content of 1.5% and a PMMA-converted weight average molecular weight of the value shown in Table 1, ASTM D12
A polyacetal copolymer having a melt index value of 27 g / 10 minutes and a melting point of 170 ° C. measured at 190 ° C. according to Method 38 (Amylas S73 manufactured by Toray Industries, Inc.
1), talc as a crystal nucleating agent (LMS3 manufactured by Fuji Talc Co., Ltd.
00) was mixed in the proportions shown in Table 1 and melt-kneaded with a uniaxial extruder having a diameter of 20 mm at a temperature of 220 ° C. and a rotation speed of 50 rpm to obtain a resin composition.

The glass transition temperature, melting temperature, crystallization temperature of the polyacetal resin at the time of temperature decrease, and crystallization start temperature at the time of temperature decrease of the obtained resin composition were measured by DSC using a temperature raising / lowering rate of 20.
It was measured at ° C / min. The crystallization temperature of the used polyacetal alone when the temperature was lowered was 140 ° C. In this example, the glass transition temperature and the decrease in the crystallization temperature of the polyacetal resin at the time of temperature decrease mean that they are compatibilized, and the increase of the crystallization start temperature at the time of temperature decrease means the improvement of the crystallization rate. To do.

The resin composition thus obtained was treated at a temperature of 180.
A sheet having a thickness of 2 mm was prepared by pressing at 0 ° C. A strip-shaped sheet having a width of 1 cm and a length of 10 cm was cut out from the obtained sheet, heat-treated in a hot air oven at 160 ° C. for 30 minutes, and the state of deformation of the sheet was visually observed. The results are also shown in Table 1.

[0077]

[Table 1]

In the compositions of the present invention described in the examples, it is found that the polylactic acid resin and the polyacetal resin are compatible with each other, from the decrease in the glass transition temperature and the decrease in the crystallization temperature upon cooling of the polyacetal. Further, the crystallization start temperature is higher than that of the comparative example, and it can be seen that the crystallization characteristics are excellent. It is also found that there is no deformation during heat treatment, and the heat resistance is excellent.

In Table 1, when both the poly (L-lactic acid) resin and the poly (D-lactic acid) resin are used to form a stereo complex, the melting temperature becomes high, and therefore 220 ° C.
The above melting temperatures are shown. Among the two melting temperatures described, in Examples 1 to 4 and 6, the low temperature side shows the melting temperature of the polyacetal resin and the high temperature side shows the melting temperature of the polylactic acid resin, and the polylactic acid resin is the stereocomplex. It is considered that the crystallization rate and the heat resistance were greatly improved by forming the polyacetal resin and containing the polyaceal resin. Further, in Example 5, the higher melting point is the melting temperature of the polylactic acid resin, but the melting peak is small and the amount of stereocomplex formed is small, but the inclusion of the polyacetal resin shows excellent characteristics.

From these results, it can be seen that the resin composition of the present invention has excellent crystallization characteristics and heat resistance.

[0081]

As described above, the resin composition of the present invention is excellent in crystallization characteristics and heat resistance, and molded articles obtained from this resin composition can be used for building civil engineering by utilizing the above characteristics. It can be used for various purposes such as members, agricultural materials, horticultural materials, electric / electronic parts, automobile parts, medical materials, clothing and daily necessities.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA14 AA15 AA20 AA21 AA22                       AA33 AA40 AA43 AB03 AB18                       AB21 AB22 AB24 AB25 AB26                       AB30 AC09 AC10 AC12 AE04                       AE05 AE07 AE17 AF43 AF45                       AH01 AH03 AH07 AH12                 4J002 BB033 BB123 BB163 BG013                       BP00W CB00X CF17W DA026                       DA036 DE046 DE216 DF016                       DG046 DH04 DH046 DJ016                       DJ036 DJ046 DJ056 EG016                       EG076 EH016 EP016 FD01                       FD02 FD09 FD13 FD16 GA00                       GB01 GK00 GN00 GQ00

Claims (11)

[Claims] 1. A resin composition comprising (A) a polylactic acid resin and (B) a polyacetal resin, wherein the polylactic acid resin comprises (A-1) L-lactic acid unit as a main component.
Polylactic acid resin containing both lactic acid resin and poly-D lactic acid resin containing D-lactic acid unit as a main component and / or (A-
2) A resin composition, which is a block copolymer comprising a poly-L-lactic acid segment containing an L-lactic acid unit as a main component and a poly-D-lactic acid segment containing a D-lactic acid unit as a main component. 2. When the total amount of the (A) polylactic acid resin and the (B) polyacetal resin is 100 parts by weight,
The amount of the (A) polylactic acid resin is 99 parts by weight or less 50
The resin composition according to claim 1, which is contained in an amount of at least part by weight. 3. When the total amount of the (A) polylactic acid resin and the (B) polyacetal resin is 100 parts by weight,
The resin composition according to claim 1, wherein the compounding amount of the (B) polyacetal resin is 99 parts by weight or more and more than 50 parts by weight. 4. The resin composition according to claim 1, wherein the polylactic acid resin (A) and the polyacetal resin (B) in the resin composition are compatibilized with each other. . 5. The (A) polylactic acid resin has a ratio of (A-1) poly (L-lactic acid) resin to poly (D-lactic acid) resin of 95: 5.
It is 5:95, or the ratio of the amount of poly-L-lactic acid segment and poly-D-lactic acid segment in the block copolymer (A-2) is 95: 5 to 5:95. 4. The resin composition according to any one of 4 above. 6. The (A) polylactic acid resin is (A-1).
It contains both a poly L lactic acid resin having 80 mol% or more of L-lactic acid units and a poly D lactic acid resin having 80 mol% or more of D-lactic acid units, or (A-2) 80 mol% of L-lactic acid units. A block copolymer comprising a poly (L-lactic acid) segment having the above and a poly (D-lactic acid) segment having a D-lactic acid unit of 80 mol% or more.
The resin composition according to item. 7. In the polylactic acid resin (A-1),
Regarding the weight average molecular weight Mw (L) of the poly L lactic acid resin and the weight average molecular weight Mw (D) of the poly D lactic acid resin, Mw
The resin composition according to any one of claims 1 to 6, wherein the larger value of (L) / Mw (D) or Mw (D) / Mw (L) is 2 or more. object. 8. The melting point of the polylactic acid resin (A) is 190.
The resin composition according to any one of claims 1 to 7, wherein the resin composition has a temperature of not less than ° C. 9. The (B) polyacetal resin is a polyacetal copolymer.
The resin composition according to claim 1. 10. The resin composition according to claim 1, further comprising a crystallization accelerator. 11. A molded article comprising the resin composition according to any one of claims 1 to 10.