JP2010111740A - Biodegradable flame retardant polyester resin composition for foaming, foamed article obtained therefrom, and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable flame retardant polyester resin composition for foaming excellent in flame retardancy, heat resistance and mechanical strength, having rheological properties which are advantageous to molding of a foamed sheet and so on; and a foamed article obtained therefrom and a molded article thereof. <P>SOLUTION: This biodegradable flame retardant polyester resin composition for foaming comprises 100 pts.mass of a biodegradable polyester resin (A), 0.01-10 pts.mass of a (meth)acrylic ester compound (B), 0.01-10 pts.mass of an organic peroxide (C), 0.1-1.4 pts.mass of an epoxy-containing chain extender (D), and 0.1-21 pts.mass of a flame retardant (E), wherein the biodegradable polyester resin (A) includes ≥70 mol% of α- and/or β-hydroxycarboxylic acid units, the flame retardant (E) is a bromine-based flame retardant (E1) and/or a phosphorus-based flame retardant (E2) and/or a camphorsulfonic acid (E3). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is obtained by melt-kneading a biodegradable polyester resin, a (meth) acrylic ester compound, an organic peroxide, an epoxy group-containing chain extender, and a flame retardant, and has flame retardancy and heat resistance. The present invention relates to a biodegradable flame-retardant polyester foaming resin composition having excellent mechanical strength and having rheological properties advantageous for molding of foams and the like having no problem in operability, a foam obtained therefrom, and a molded product thereof. .

  Conventionally, plastic foams that are characterized by light weight, buffer properties, heat insulation properties, moldability, and the like have been mainly used as packaging containers and buffer materials. These conventionally used plastics themselves are made of petroleum resources, and remain in the natural environment when disposed at the time of disposal, and when incinerated, they generate harmful gases and incinerators. There is a problem of deteriorating, which is a social problem.

  In recent years, in order to solve these problems, polylactic acid, polybutylene succinate, polycaprolactone, polyethylene succinate, polybutylene terephthalate that can be decomposed by moisture or microorganisms and can be composted in compost There is a demand for a foam made of a biodegradable resin such as adipate. Among these, polylactic acid, in particular, is a plant-derived resin obtained by polymerizing lactic acid obtained by fermenting various starches and sugars, and eventually becomes carbon dioxide gas and water, which is ideal for environmental recycling on a global scale. As a typical resin, it has begun to be used for various purposes.

  Polylactic acid has been applied and examined as a biomass-derived resin or a biodegradable resin, and its application is being developed in various fields. Particularly in the field of injection molding, which has heretofore been difficult to apply due to a slow crystallization rate, modified polylactic acid having high crystallinity and excellent heat-resistant moldability has been produced. As a result, it has been applied to various fields, and for example, it is going to be developed to things that cannot be applied conventionally, such as home appliances and automobile parts.

  For foam production, a resin with high melt tension is required, but in biodegradable polyester, after biodegradable polyester resin is produced, it is crosslinked by melt-kneading with peroxides or reactive compounds. Much research has been conducted in that the method of generating a simple is easy and the degree of branching can be freely changed. However, the acid anhydride and polyvalent carboxylic acid used in Patent Document 1 are not practical because they tend to have spots in reactivity and need to be reduced in pressure. The polyvalent isocyanate used in Patent Documents 2 and 3 has a molecular weight that tends to decrease during remelting, and there is a problem in safety during operation.

  The present inventors have used a biodegradable polyester resin composition such as polylactic acid, a biodegradable polyester resin composition having excellent mechanical strength and heat resistance and having rheological properties advantageous for foam molding, and the foam thereof. Body and molded container have been proposed (Patent Documents 4 and 5). However, in these methods, although the melt tension and the crystallization speed are improved and heat resistance can be imparted, flame retardancy has not been improved. When considering application to home appliances, automobile parts, building materials, etc., imparting flame retardancy remains an important issue.

  Patent Document 6 employs a method for producing a flame-retardant polylactic acid-based resin mainly composed of polylactic acid and to which a metal oxide is added. However, since the addition amount is as large as 20 to 60 parts by mass, elongational viscosity is used. When the resin described in Patent Document 6 is applied to the foam as it is, foam breakage tends to occur, the moldability is remarkably deteriorated, and a foamed molded article having a good appearance cannot be obtained.

  Patent Documents 7 and 8 adopt a method of adding a phosphorus-based flame retardant, bromine-based flame retardant, chlorine-based flame retardant, nitrogen compound-based flame retardant, silicone-based flame retardant, and other inorganic flame retardants to polylactic acid resin. However, since a crosslinking agent, an organic peroxide, and a chain extender are not contained, a foamed molded article having a low melt viscosity, elongational viscosity and strain curability and a good expansion ratio and appearance cannot be obtained.

Patent Document 9 discloses a resin composition and a foamed molded article containing 3 to 10 parts by mass of a phosphorus-based flame retardant and 1 to 5 parts by mass of a polyisocyanate compound in a polylactic acid resin. However, sufficient flame retardancy cannot be obtained by adding 10 parts by mass of the phosphorous flame retardant alone. Moreover, although the viscosity is provided by the isocyanate compound, since the isocyanate compound exhibits a decomposition reaction as well as a thickening reaction, a sufficient thickening reaction does not proceed.
Japanese Patent Laid-Open No. 11-60928 Japanese Patent No. 2571329 JP 2000-17037 A JP 2003-128901 A JP 2004-217288 A JP 2008-150560 A JP 2005-89546 A JP 2004-190025 A JP 2007-138062 A

  The present invention is intended to solve the above-described problems, and is used for foaming biodegradable flame-retardant polyesters having rheological properties advantageous for molding foam sheets having excellent flame retardancy, heat resistance, and mechanical strength. It is an object of the present invention to provide a resin composition, a foam obtained from the resin composition, and a molded product thereof.

As a result of intensive studies to solve such problems, the present inventors have obtained a biodegradable polyester resin, a (meth) acrylic acid ester compound, an organic peroxide, an epoxy group-containing chain extender, a flame retardant, It is found that the resin composition obtained by melt-kneading is not only excellent in flame retardancy but also has rheological properties excellent in foam moldability due to the improvement in melt viscosity and the expression of strain-hardening in elongational viscosity measurement, Further, the molded product obtained from this has been found to have a high crystallization rate and high mechanical strength while maintaining heat resistance, and has reached the present invention.
That is, the gist of the present invention is as follows.
(1) Biodegradable polyester resin (A) 100 parts by mass, (meth) acrylic acid ester compound (B) 0.01 to 10 parts by mass, organic peroxide (C) 0.01 to 10 parts by mass A resin composition obtained by melt-kneading 0.1 to 1.4 parts by mass of an epoxy group-containing chain extender (D) and 0.1 to 21 parts by mass of a flame retardant (E), which is biodegradable The polyester resin (A) is a resin containing 70 mol% or more of α- and / or β-hydroxycarboxylic acid units, and the flame retardant (E) is a brominated flame retardant (E1) and / or a phosphorus flame retardant. A resin composition for foaming a biodegradable flame retardant polyester, which is (E2) and / or camphorsulfonic acid (E3).
(2) The amount of the brominated flame retardant (E1) is 3 to 20 parts by mass with respect to 100 parts by mass of the biodegradable polyester resin (A), and the amount of the phosphorus flame retardant (E2) is 3 to 3 parts by mass. The resin composition as described in (1), wherein the content is 20 parts by mass and the amount of camphorsulfonic acid (E3) is 0.1 to 1.0 parts by mass.
(3) The (meth) acrylic acid ester compound (B) has two or more (meth) acrylic groups in the molecule, or one or more (meth) acrylic groups and one or more glycidyl groups or The resin composition according to (1) or (2), which is a compound having a vinyl group.
(4) The resin composition according to any one of (1) to (3), wherein the α- and / or β-hydroxycarboxylic acid unit is D-lactic acid, L-lactic acid, or a mixture thereof.
(5) The resin composition according to any one of (1) to (4), wherein the resin composition has a crystallization rate index of 10 (min) or less.
(6) A biodegradable flame-retardant polyester resin foam obtained by foam-molding the resin composition according to any one of (1) to (5) above.
(7) A biodegradable flame retardant polyester resin molded article obtained by molding the foam according to (6).

  According to the present invention, a biodegradable flame retardant polyester foaming resin composition having excellent flame retardancy, high mechanical strength, and high heat resistance and having rheological properties advantageous for molding of foams, etc. can be easily and cost effectively. It is possible to provide a foam and a molded body excellent in flame retardancy and foamability using this resin.

Hereinafter, the present invention will be described in detail.
In the present invention, the biodegradable polyester resin (A) is a resin containing 70 mol% or more of α- and / or β-hydroxycarboxylic acid units. Examples of α- and / or β-hydroxycarboxylic acid units include D-lactic acid, L-lactic acid, glycolic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 3-hydroxycaproic acid, and the like. There may be.
Therefore, as the biodegradable polyester resin (A) used in the present invention, poly (D-) and / or L-lactic acid, poly (glycolic acid), poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid) , Poly (3-hydroxycaproic acid), and / or a copolymer thereof, and / or a mixture thereof.
In view of the heat resistance and mechanical strength of the molded article, the biodegradable polyester resin (A) has a melting point of preferably 120 ° C. or higher, more preferably 150 ° C. or higher. For the same reason, the content of the α- and / or β-hydroxycarboxylic acid unit needs to be 70 mol% or more, preferably 80 mol% or more. Among the biodegradable polyester resins (A), poly (D- and / or L-lactic acid) is preferably used from the viewpoint that industrial mass production is possible.

  The biodegradable polyester resin (A) is usually produced by a well-known melt polymerization method or by further using a solid phase polymerization method. Further, poly (3-hydroxybutyric acid), poly (3-hydroxyvaleric acid), and the like can be produced by microorganisms.

  A lactic acid polymer can also be produced by a conventionally known method. Examples of the polymerization method include, for example, a method in which lactic acid is directly dehydrated and condensed, a method obtained by ring-opening polymerization of lactide, which is a cyclic dimer of lactic acid, and the like. Moreover, these polymerization reactions may be performed in a solvent, and when necessary, the reaction may be efficiently performed using a catalyst or an initiator. These methods may be appropriately selected in consideration of the necessary molecular weight and melt viscosity.

  The biodegradable polyester resin (A) used in the present invention may have other biodegradable properties as required, as long as the heat resistance of poly (α- and / or β-hydroxycarboxylic acid is not significantly impaired. Polyester resin components can also be copolymerized or mixed.Other biodegradable polyester resins include aliphatic polyesters composed of diols and dicarboxylic acids such as poly (ethylene succinate) and poly (butylene succinate). Poly (ω-hydroxyalkanoate) typified by poly (ε-caprolactone), poly (butylene succinate-co-butylene terephthalate) and (butylene adipate) which are biodegradable even if they contain an aromatic component co-butylene terephthalate), polyester amide, polyester carbonate, Polysaccharides such as Pung and the like.

  The weight average molecular weight of the biodegradable polyester resin (A) used in the present invention is preferably 50,000 to 1,000,000, and more preferably 80,000 to 1,000,000. More preferred. A weight average molecular weight of less than 50,000 is not preferable because the melt viscosity of the resin composition is too low. On the contrary, if this exceeds 1,000,000, the moldability of the resin composition may decrease rapidly, which is not preferable.

  In the biodegradable flame-retardant polyester foaming resin composition of the present invention, the biodegradable polyester resin (A) is melt-kneaded together with the (meth) acrylic acid ester compound (B) and the organic peroxide (C). is required. By melt-kneading these, the degree of cross-linking of the biodegradable polyester resin (A) can be increased, the degree of branching can be adjusted, and the moldability such as extrusion foaming can be improved.

In the present invention, the (meth) acrylic acid ester compound (B) acting as a cross-linking agent is highly reactive with the biodegradable polyester resin (A), hardly causes a monomer to remain, has relatively little toxicity, and the resin is also colored. Since there are few, the compound which has a 2 or more (meth) acryl group in a molecule | numerator, or a 1 or more (meth) acryl group and 1 or more glycidyl group or a vinyl group is preferable.
Specific examples of the (meth) acrylic acid ester compound (B) include glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy polyethylene glycol mono Methacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol dimethacrylate, polypropylene glycol diacrylate, polytetramethylene glycol dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate Copolymer At best, further butanediol methacrylate, butanediol acrylate.
In the present invention, it is necessary to blend and knead 0.01 to 10 parts by mass of the (meth) acrylic acid ester compound (B) to 100 parts by mass of the biodegradable polyester resin (A). The blending amount is preferably 0.02 to 8 parts by mass, and more preferably 0.05 to 5 parts by mass. When the blending amount of the (meth) acrylic ester compound (B) is less than 0.01 parts by mass, the degree of crosslinking is insufficient, and when it exceeds 10 parts by mass, the degree of crosslinking is too strong and the operability is hindered. Because it comes out, it is not preferable.

In the present invention, the organic peroxide (C) that functions as a radical polymerization initiator is preferably one having good dispersibility. Specifically, benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxide) are preferable. Oxy) cyclododecane, butylbis (butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) Hexin, butyl peroxycumene and the like can be mentioned.
In the present invention, it is necessary to mix and knead 0.01 to 10 parts by mass of the organic peroxide (C) with respect to 100 parts by mass of the biodegradable polyester resin (A). The amount is preferably 0.1 to 5 parts by mass, and more preferably 0.15 to 3 parts by mass. When the amount of the organic peroxide (C) is less than 0.01 parts by mass, the degree of crosslinking is insufficient, and when it exceeds 10 parts by mass, the reactivity is saturated, which is not preferable in terms of cost. The organic peroxide (C) may not remain in the resin composition after melt-kneading.

In the resin composition of the present invention, the epoxy chain extender (D) may be melt kneaded by blending 0.1 to 1.4 parts by mass with respect to 100 parts by mass of the biodegradable polyester resin (A). It is necessary, and it is preferable that the compounding quantity is 0.1-1.0 mass part. When the blending amount of the epoxy chain extender (D) is less than 0.1 parts by mass, the resin composition has a low melt viscosity, the foamability is lowered, and when the blending amount exceeds 1.4 parts by mass, the resin composition The melt viscosity of the product is too high, making foam molding impossible.
The epoxy chain extender (D) preferably has a weight average molecular weight of 3000 to 15000 and an epoxy value of 2 to 5 meq / g.
Specific examples of the epoxy chain extender (D) applicable to the present invention include BASF's Joncryl ADR-4300, ADR-4368, ADR-4380, Toagosei Alfon UG-4040, and UG-4068.

The resin composition of the present invention contains a flame retardant (E), and the flame retardant (E) is a brominated flame retardant (E1) and / or a phosphorus flame retardant (E2) and / or camphorsulfonic acid (E3). It is necessary.
As the brominated flame retardant (E1), one having a bromine content of 40 to 70% by weight and a 5% weight reduction temperature of 250 to 300 ° C. can be preferably used. If the bromine content is less than 40% by weight, the flame retardant effect is low, so a large amount of flame retardant needs to be added, which makes foam molding difficult. On the other hand, if the 5% weight loss temperature is less than 250 ° C., the flame retardant decomposes during processing, resulting in problems such as reduced flame retardancy and resin coloring. Conversely, if the 5% weight loss temperature exceeds 300 ° C., it is difficult to decompose during combustion and flame retardancy is reduced. The 5% weight loss temperature is measured by thermogravimetric analysis (TGA) under a nitrogen atmosphere under a temperature rising condition of 10 ° C./min.
Specific examples of the brominated flame retardant (E1) applicable to the present invention include Pyroguard SR-720, Piroguard SR-130, Piroguard SR-600A, and Nippon Kasei TAIC-6B manufactured by Daiichi Kogyo Seiyaku. .

As the phosphorus-based flame retardant (E2), those having a phosphorus content of 5 to 30% by weight can be preferably used. Specifically, aromatic condensed phosphates, phosphates, melamine polyphosphates, polyphosphorus An ammonium acid etc. are mentioned.
Specific examples of the phosphorus-based flame retardant (E2) applicable to the present invention include ADEKA FP-2100J, FP-2200, Daihachi PX-200, Clariant Exolit OP-1312, OP-930, and the like. .

  The camphorsulfonic acid (E3) used as a flame retardant in the present invention may be any of L-form, D-form, and DL-form.

  In the resin composition of the present invention, the blending amount of the flame retardant (E) needs to be 0.1 to 21 parts by mass with respect to 100 parts by mass of the biodegradable polyester resin (A). Moreover, when using a brominated flame retardant (E1), it is preferable that the compounding quantity is 3-20 mass parts, and also when using a phosphorus flame retardant (E2), the compounding quantity is 3-20 mass parts. When camphorsulfonic acid (E3) is used, the blending amount is preferably 0.1 to 1.0 part by mass. If the blending amount is less than the above range, a flame retardant resin composition cannot be obtained, and if the blending amount exceeds the above range, the flame retardancy is improved, but the melt viscosity, elongational viscosity, distortion The curing coefficient is lowered and the foamability is lost.

  In the present invention, the melt viscosity (MFR, JIS K7210 compliant, 190 ° C., 2.16 kgf) of the resin composition is preferably 0.4 to 20.0 g / 10 minutes, more preferably 1.0 to 10.0 g / 10 minutes. 1.0 to 6.0 g / 10 min is more preferable. If the MFR exceeds 20 g / 10 min, the melt viscosity is too low, leading to bubble breakage, and the expansion ratio is difficult to increase. On the other hand, if the MFR is less than 0.4 g / 10 min, the melt viscosity is too high, and bubbles cannot grow, making it difficult to increase the expansion ratio.

In the biodegradable flame retardant polyester foaming resin composition of the present invention, it is preferable to add a crystal nucleating agent, a foaming nucleating agent, and a foaming aid.
The crystal nucleating agent promotes crystallization of the biodegradable flame retardant polyester foaming resin, and is an important factor for maintaining heat resistance and dimensional stability. Crystal nucleating agents include compounds that are effective in promoting crystallization among inorganic fillers and organic compounds, and any nucleating agent may be used or may be used in combination. For example, inorganic fillers include layered silicate, talc, titanium oxide, silicon oxide calcined perlite, kaolin zeolite, bentonite, fine silica powder, borax, zinc borate, aluminum hydroxide, glass, limestone, calcium silicate, calcium sulfate, Organic compounds such as calcium carbonate, sodium hydrogen carbonate, magnesium carbonate, aluminum oxide include erucic acid amide, ethylene bis stearic acid amide, citric acid, ethylene bis oleic acid amide, sulfonate, phthalocyanine compound, melamine compound, phosphone Examples thereof include acid salts, hydrazide compounds, trimesic acid carboxylic acid ester compounds, and the like.
The foam nucleating agent is effective for forming foam nuclei during foam molding and growing foam from the nuclei, and the foaming aid is effective for uniformly dispersing the foam.
As the foam nucleating agent, in inorganic systems, diatomaceous earth, calcined perlite, kaolin zeolite, bentonite, clay, silica fine powder, borax, zinc borate, aluminum hydroxide, talc, glass, limestone, calcium silicate, calcium sulfate, carbonic acid Calcium, sodium hydrogen carbonate, magnesium carbonate, aluminum oxide, ferric carbonate and the like, and organic type include charcoal, cellulose, starch, citric acid, cellulose derivatives and other organic fillers, etc. They can be used together. Among these, talc has the effects of both a foam nucleating agent and a crystal nucleating agent, and is most effective if it is in the form of fine powder. The addition amount of the foam nucleating agent is preferably 0.1 to 5% by mass. If it is less than 0.1% by mass, the effect as a foam nucleating agent is not recognized, and if it exceeds 5% by mass, it is not preferable because it leads to bubble breakage and a reduction in the expansion ratio.
Examples of the foaming aid include fatty acid salts such as calcium stearate, magnesium stearate, and aluminum stearate. The addition amount of the foaming aid is preferably 0.01 to 2% by mass. If it is less than 0.01% by mass, the effect as a foaming aid is not recognized, and if it exceeds 2% by mass, the growth of foaming nuclei and foaming is inhibited, which is not preferable.

  As long as the properties of the biodegradable flame-retardant polyester foaming resin composition are not significantly impaired, pigments, fragrances, dyes, matting agents, heat stabilizers, antioxidants, plasticizers, lubricants, mold release agents It is also possible to add a light resistance agent, a weather resistance agent, a flame retardant, an antibacterial agent, a surfactant, a surface modifier, an antistatic agent, a filler, a terminal blocking agent, and the like. As the heat stabilizer or antioxidant, for example, hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, or mixtures thereof can be used. Inorganic fillers include zinc carbonate, wollastonite, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon, carbon black, zinc oxide, antimony trioxide, zeolite, Examples thereof include hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, glass fiber, and carbon fiber. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. Examples of the terminal blocking agent include carbodiimide compounds, oxazoline compounds, and epoxy compounds.

  The flame retardancy of the biodegradable flame retardant polyester foamed resin foam of the present invention and the molded product thereof is preferably V-0, V-1 or V-2 in the UL-94 flame retardant test. In the present invention, even when V-2 is not reached in the UL-94 flame retardant test, if the flame retardancy evaluated by the method described in the Example column is “A” evaluation, It was judged that flammability was obtained.

  The resin composition for foaming the biodegradable flame retardant polyester of the present invention can have high heat resistance by crystallization during molding. In order to increase the crystallinity rapidly, it is necessary to increase the crystallization speed. The resin composition for foaming a biodegradable flame retardant polyester of the present invention preferably has a crystallization rate index measured by the method described in the example column of 10 (min) or less, and 5 (min) or less. It is more preferable.

  The biodegradable flame-retardant polyester resin foam of the present invention and the molded product thereof need to contain bubbles from the viewpoint of lightness, heat insulation, and heat retention. In this case, the foaming ratio of the resin is preferably 1.2 times to 50 times. When the foaming ratio of the resin is low, it is easy to obtain strength even with a thin wall, and when the foaming ratio is 4 times or more, the resin is light and has excellent heat insulation and vibration absorption. However, if it exceeds 50 times, the mechanical strength may be insufficient.

  The bubble form is not particularly limited, but is preferably a closed cell. Moreover, as a bubble diameter, it is more preferable that it is 0.001-2 mm, and also 0.01-2 mm. If it is less than 0.001 mm, the lightweight property of the foam is inferior, and if it exceeds 2 mm, the strength may be insufficient or the quality of the foam may be impaired.

  In order to make the biodegradable flame retardant polyester foaming resin composition contain bubbles, a general foaming agent can be used. The type of foaming agent is not particularly limited, and examples thereof include inorganic inert gas systems such as carbon dioxide, nitrogen and air, azodicarbonamide, azobisisobutyronitrile, 4,4′-oxybisbenzene. Examples include pyrolytic chemical foaming agents such as sulfonyl hydrazide, benzenesulfonyl hydrazide, and baking soda, and evaporating foaming agents such as propane, butane, pentane, hexane, and alternative chlorofluorocarbons.

  As a method of incorporating bubbles into the biodegradable flame retardant polyester foaming resin composition of the present invention, a resin is foamed to a desired foaming ratio in advance using a foaming agent, and then a sheet or the like is produced. There are a method of processing and a method of mixing a foaming agent into a resin when processing a biodegradable flame-retardant polyester foaming resin into a product shape.

Next, a preferred method for producing the biodegradable flame-retardant polyester foaming resin composition of the present invention and a foamed product and a molded product therefrom will be described.
Biodegradable flame retardant polyester foaming resin composition comprises biodegradable polyester resin (A), (meth) acrylic acid ester compound (B), organic peroxide (C), epoxy group-containing chain extender (D) The flame retardant (E) and, if necessary, a foaming nucleating agent and a foaming aid can be mixed and melt-kneaded by a conventionally known method. The mixing method and the mixing apparatus are not particularly limited, but it is preferable from the industrial and quality viewpoint to continuously measure and mix. For example, a dry powder blend of a measured powdery organic peroxide (C), an epoxy group-containing chain extender (D), a flame retardant (E), etc. on a biodegradable polyester resin (A) chip, It is melt-kneaded with a screw extruder or a twin screw extruder, and the (meth) acrylate compound (B) is injected from the middle of the extruder. Preferably, the (meth) acrylic ester compound (B), the organic peroxide (C) and the mixed solution are injected from the middle of the extruder. In melt kneading, not only screw kneading but also kneading with a static mixer and / or a dynamic mixer may be performed thereafter. For the purpose of imparting a function to the foam, for example, when adding a functional agent such as a colorant, a master batch to which a functional agent has been added is prepared in advance, and this can be performed using a mixing device such as a jet color. It can also be fed to the extruder after being mixed with the raw materials.
The resin composition thus melt-kneaded is extruded into a strand shape and cut into an appropriate length after cooling, whereby pellets of the biodegradable flame-retardant polyester foaming resin composition can be produced.

The method for producing the biodegradable flame retardant polyester resin foam is not particularly limited, and the resin composition for foaming the biodegradable flame retardant polyester produced by the above method is used for melt extrusion foaming, beads It can be produced by a foaming method.
In the melt extrusion foaming method, first, pellets of the resin composition produced by the above method are dried and supplied to a melt extrusion foaming apparatus. The cylinder temperature at this time is preferably in the range of Tm + 10 ° C. to 50 ° C., where Tm is the melting point of the resin composition. Since the vicinity of the outlet of the foaming apparatus is a cooling zone for increasing the melt viscosity, it is preferably Tm + 10 ° C. to −20 ° C. When supplying the pellets, a lubricant, a foaming agent, a foaming nucleating agent, other functional materials, or the like may be dry blended. When the foaming agent is carbon dioxide gas or an evaporating foaming agent, a fixed amount is supplied from the center of the machine base, dissolved and dispersed, and then foamed and discharged through a T die or a circle die. By uniformly cooling and winding up the discharged foamed sheet-like material, the biodegradable flame-retardant polyester resin foam of the present invention can be produced.

A biodegradable flame retardant polyester resin molding can be produced by heat-molding the biodegradable flame retardant polyester resin foam. This heat treatment molding improves the heat resistance of the resulting molded body. As the heat treatment forming method, vacuum forming, pressure forming, drawing forming such as vacuum / pressure forming, etc. can be employed. At the time of molding, the drawing temperature and mold temperature are set to Tg (glass transition temperature) + 20 ° C. or higher and Tm−20 ° C. or lower of the biodegradable polyester resin used. By doing so, a molded body that crystallizes and has high heat resistance is obtained. In order to further accelerate the crystallization of the resin, it is more preferable to set the mold temperature in a temperature range of Tc (crystallization temperature) −20 ° C. or higher and Tc + 20 ° C. or lower. Alternatively, the biodegradable flame retardant polyester resin foam sheet can be heat treated at Tg + 20 ° C. to Tm-20 ° C. for a predetermined time, or heat set at Tg + 20 ° C. to Tm-20 ° C. for a predetermined time after molding.
When the heat treatment temperature is less than Tg + 20 ° C., the crystallinity of the obtained molded body cannot be sufficiently increased, and the heat resistance becomes insufficient. On the other hand, if it exceeds Tm−20 ° C., uneven thickness may occur or orientation may be lost, and strength and quality may be reduced. In addition, problems such as blowdown due to a decrease in viscosity also occur. The time for holding at a temperature of Tg + 20 ° C. to Tm−20 ° C. depends on the crystallization rate index of the biodegradable polyester resin to be used, and thus cannot be specified unconditionally, but in the mold controlled to a temperature within the above range. And at least 3 seconds, preferably 5 seconds, more preferably 8 seconds or more. When the time is shorter than 3 seconds, the crystallinity cannot be sufficiently increased, so that the heat resistance is lowered.

Examples of the bead foaming method include a method in which foamed particles are prepared from pellets of the resin composition produced by the above-described method, and then molded to obtain a foamed molded product.
The foamed particles can be produced by drying pellets of the resin composition, placing them in a pressure-resistant sealed container, filling and impregnating a foaming agent to obtain impregnated pellets, and then foaming the pellets. The impregnation temperature is preferably Tm-20 ° C to Tm + 20 ° C, and more preferably Tm-10 ° C to Tm + 10 ° C. The pressure of the foaming agent at the time of impregnation varies depending on the foaming ratio of the target foam and the fineness of the cells, but is adjusted to be in the range of 0.5 to 30 MPa, preferably 5 to 20 MPa. The impregnation time is usually preferably 1 minute to 24 hours. Expanded particles can be produced by heat-treating the obtained impregnated pellets. A known heat treatment method and apparatus can be used. For example, the impregnated pellets can be foamed by heating with hot air, steam, radiant heat, or the like. The heat treatment temperature is preferably Tm-60 ° C to Tm + 20 ° C. When the temperature is outside this range, there is a problem that foaming does not occur at all, the foaming ratio is low, and the foamed particles and foamed molded article obtained are melted.
Further, the foamed particles are obtained by drying the pellets of the resin composition and supplying the pellets to the extruder, and by supplying a fixed amount of the foaming agent from the center of the machine base, dissolving and dispersing, and then foaming and discharging the strands. The strand can also be produced by cooling and cutting. The cylinder temperature is preferably in the range of Tm + 10 ° C. to 50 ° C. Since the vicinity of the outlet of the foaming apparatus is a cooling zone for increasing the melt viscosity, it is preferably Tm + 10 ° C. to −20 ° C.

By filling the foamed particles produced by the above method into a mold and further heating, a foamed molded article of any shape can be obtained. A known apparatus can be used as an apparatus for molding. For example, a molding machine for expanded polystyrene or expanded polyolefin can be used.
In addition, by filling the above-mentioned impregnation pellets in a mold and heating, it is also possible to obtain a foamed molded article from the impregnated pellets in one step without going through the step of producing foamed particles. Compared to the production of a foamed molded article by a two-stage heat treatment, the one-stage is preferable in terms of securing the adhesion between particles at the time of molding and the transportation cost of the foamed particles.
Alternatively, the foamed particles may be filled with an inorganic inert gas to produce foamed particles with internal pressure, and then foam-molded. The internal pressure-applied foamed particles can be produced by placing the foamed particles in a pressure-resistant sealed container, filling with an inorganic inert gas, and applying an internal pressure. The pressure during filling is preferably 0.1 to 3 MPa, more preferably 0.2 to 1 MPa, the temperature is preferably not higher than the glass transition temperature of the resin composition, more preferably 40 ° C. or lower, and the time is preferably 30 minutes or longer. .
By filling the internal pressure-applied foamed particles in a mold of an in-mold foam molding machine and heating the foamed particles, the foamed particles can be foamed and the particles can be fused. Examples of the heating medium used in the in-mold foam molding include dry hot air, water vapor, and radiant heat, but it is preferable to use water vapor that has a large amount of heat and can be heated at once and can promote crystallization. A known apparatus can be used for in-mold foam molding. For example, a molding machine for expanded polystyrene or expanded polyolefin can be used. The temperature of the heating medium at the time of in-mold foam molding is preferably in the range of Tm−60 ° C. to Tm + 20 ° C., depending on the type of heating medium and the size of the mold. When the temperature is outside this range, there is a problem that foaming does not occur at all, the foaming ratio is low, and the foamed particles and foamed molded article obtained are melted. In addition, after the internal pressure-applied foamed particles are heated at 50 to 90 ° C. and secondarily foamed without filling the mold, the internal pressure is applied again, and then the mold is filled and heated to perform in-mold foam molding. May be.

  The biodegradable flame retardant polyester resin foam and molded article of the present invention have flame retardancy, light weight, heat resistance, and excellent mechanical properties. For example, in the field of home appliances and electronic equipment, , Refrigerators, air conditioner insulation materials, washing machine sound insulation materials, lighting reflectors, speaker diaphragms, etc. In addition, in the construction and civil engineering fields, insulation materials, sound insulation walls, wall materials, wallpaper, flooring materials, In addition, since it has high heat resistance, it can be used for automobile applications. For example, it can be used for ceiling materials, roof heat insulating materials, cushion materials, interior parts, and the like. In addition, it can be used for industrial materials.

  Next, the present invention will be specifically described based on examples. In addition, the measurement and evaluation of various characteristics in the examples were performed by the following methods.

Molecular weight:
Using a gel permeation chromatography (GPC) apparatus (manufactured by Shimadzu Corporation) equipped with a differential refractive index detector, analysis was performed at 40 ° C. using tetrahydrofuran (THF) as an eluent, and the molecular weight was determined in terms of standard polystyrene. A sample that was hardly soluble in THF was dissolved in a small amount of chloroform and then diluted with THF to prepare a sample.

Glass transition temperature (° C), melting point (° C):
Using a differential scanning calorimeter DSC-7 manufactured by Perkin Elma Co., the temperature was measured according to JIS K 7123 at a temperature rising rate of 20 ° C./min.

Melt viscosity (MFR) (g / 10 min):
In JIS K7210, when the melting point is 180 ° C. or lower, it is measured at a temperature of 190 ° C. and a load of 2.16 Kgf according to the method described in the D condition. When the melting point exceeds 180 ° C., it is described in the M condition. According to the method, the temperature was 230 ° C. and the load was 2.16 Kgf.

Crystallization rate index (° C) (see Fig. 1):
Using a DSC apparatus (Pyrisl DSC manufactured by PerkinElmer Co., Ltd.), the temperature was raised at 20 ° C. → 200 ° C. (+ 500 ° C./min), held at 200 ° C. for 5 minutes, and then at 200 ° C. → 0 ° C. (−500 ° C./min). After lowering the temperature, the temperature was maintained at 0 ° C. for 5 minutes, the temperature was raised from 0 ° C. to 90 ° C. (+ 500 ° C./min), and then maintained at 90 ° C. for crystallization. When the finally reached crystallinity was 1, the time when the crystallinity reached 0.5 was determined as the crystallization rate index (minutes).

Formability:
The thickness unevenness due to sink marks, which is a defect during injection molding, was measured and evaluated to the following rank.
A: Thickness variation less than 0.01 mm B: Thickness variation 0.01-0.1 mm
X: Thickness unevenness of 0.1 mm or more

Flame retardance:
(1) Test piece preparation method / injection molded article: A molded article having a length of 127 mm, a width of 12.7 mm and a thickness of 0.8 mm produced by an injection molding method was used.
-Foam sheet: A foam sheet prepared by the melt extrusion foaming method was cut into a length of 127 mm, a width of 12.7 mm, a thickness of 0.5 to 2.5 mm, and a weight of 1.8 to 2.1 g.
(2) Evaluation method The test piece produced by the above-described method was evaluated for flammability in accordance with the UL Standard 94 vertical combustion test method of Underwriters Laboratory. That is, the test piece was kept vertical, the flame of the burner was removed after indirect flame for 10 seconds at the lower end, and the time when the fire that ignited the test piece disappeared was measured. Next, at the same time when the fire was extinguished, the second flame contact was started for 10 seconds, and the time when the ignited fire was extinguished was measured in the same manner as the first time. Moreover, it was also evaluated at the same time whether or not the cotton under the test piece was ignited by the falling fire type.
The combustion rank was given according to the above-mentioned UL-94 standard from the 1st time and the 2nd combustion time, the presence or absence of the ignition of cotton, etc. The rank of flame retardancy was in accordance with the vertical combustion test method of UL-94 standard. That is, V-0 is the highest, and the flame retardance decreases as V-1 and V-2 are obtained. For those where the combustion progressed to the clamp part of the test piece, ranks A to C were given according to the combustion time, and only the rank A was evaluated as having flame retardancy.
A: Combustion time 25 seconds or less B: Combustion time 26-60 seconds C: Combustion time 61 seconds or more

Foaming ratio:
The apparent density (g / cm ³ ) was calculated by dividing the mass of the foam by the volume increased when the obtained foam was immersed in water. Next, the expansion ratio was calculated by dividing the true density of the resin constituting the foam by the apparent density of the foam.

Foamability:
Based on the expansion ratio, the foamed state was evaluated.
◎: Foaming ratio 5.0 times or more ○: Foaming ratio 4.0 to 4.9 times Δ: Foaming ratio 3.0 to 3.9 times ×: Foaming ratio 2.9 times or less In addition, the following standards for foamed particles Evaluated.
◎: Foaming ratio 10.0 times or more ○: Foaming ratio 9.9 to 6.0 times Δ: Foaming ratio 5.9 to 3.0 times ×: Foaming ratio 2.9 times or less

Heat-resistant:
A sample piece 20 cm long x 20 cm wide was prepared from the foam sheet, treated with a hot air dryer at a temperature of 100 ° C. for a treatment time of 30 minutes, the shrinkage rate of the sample piece was measured, and the state thereof was observed. Evaluation was performed.
A: There is no change in the shrinkage and the surface state.
○: Shrinkage rate is less than 3% and there is no change in the surface state.
(Triangle | delta): There exists a shrinkage | contraction rate in 3 to 10%, the surface is rough and has deform | transformed.
X: The shrinkage rate exceeds 10%, the surface is rough and the shape is distorted.

The raw materials used in Examples and Comparative Examples are as follows.
・ Biodegradable polyester resin (A)
(A): Polylactic acid (manufactured by Nature Works, weight average molecular weight 125,000, MFR 13 g / 10 min, L-form 99%, D-form 1%, crystallization rate index 92)
(B): Polylactic acid (manufactured by Nature Works, weight average molecular weight 11 million, MFR 23 g / 10 min, L-form 95%, D-form 5%, crystallization rate index> 100)
(C): Polylactic acid (manufactured by Nature Works, weight average molecular weight 180,000, MFR 3.5 g / 10 min, L-form 90%, D-form 10%, crystallization rate index> 100)
(D): Polylactic acid (manufactured by Nature Works, weight average molecular weight 170,000, MFR 5.0 g / 10 min, L-form 80%, D-form 20%, crystallization rate index> 100)

・ (Meth) acrylic acid ester compound (B)
DEGDM: Diethylene glycol dimethacrylate (manufactured by NOF Corporation, BREMMER PDE50)
GM: Glycidyl methacrylate (Nippon Yushi Co., Bremer G)

・ Organic peroxide (C)
(e): Di-t-butyl peroxide (Nippon Yushi Perbutyl D)
(f): 2.5-dimethyl-2.5-di (t-butylperoxy) hexane (Perhexa 25B-40 manufactured by Nippon Oil & Fats. Used by dry blending in advance with a biodegradable polyester resin.)

・ Epoxy group-containing chain extender (D)
ADR-4368: Trifunctional epoxy chain extender (manufactured by BASF, Joncryl ADR-4368, weight average molecular weight 6800, epoxy value 3.5 meq / g)

・ Brominated flame retardant (E1)
SR-720: Brominated aliphatic aromatic compound (Daiichi Kogyo Seiyaku, Piroguard SR-720, bromine content 67%, 5% weight loss temperature 270 ° C.)
TAIC-6B: (2,3-dibromopropyl) isocyanurate (manufactured by Nippon Kasei, TAIC-6B, bromine content 66%, 5% weight loss temperature 285 ° C.)
・ Phosphorus flame retardant (E2)
OP-1312: Organophosphate compound (manufactured by Clariant, Exolit OP-1312, phosphorus content 19%)
PX-200: Aromatic condensed phosphate ester (Daihachi Chemical Industry, PX-200, phosphorus content 9%)
・ Camphorsulfonic acid (E3)
Camphorsulfonic acid (manufactured by CHINA CAMPHOR, melting point 195 ° C., DL form)

Examples 1-29, Comparative Examples 1-15
Using a biaxial extrusion kneader (Ikegai PCM-45, melting temperature-extrusion head temperature: 200 ° C., screw rotation 150 rpm, discharge rate 25 kg / h), 100 parts by mass of the biodegradable polyester resin (A) and The types and parts by mass of brominated flame retardant (E1), phosphorus flame retardant (E2), camphorsulfonic acid (E3), and epoxy group-containing chain extender (D) shown in Table 1 were supplied. Further, 2 parts by mass of talc (manufactured by Hayashi Kasei, average particle size 2.5 μm) was added as a foam nucleating agent. From the middle of the kneading machine, using a liquid fixed amount supply pump, 7 parts by mass of the plasticizer acetyltricitric acid containing the types and parts by mass of (meth) acrylic acid ester compound (B) and organic peroxide (C) shown in Table 1 The solution dissolved in was injected, the resin composition was extruded, and processed into pellets. After the pellets were dried, the physical properties as a resin composition were evaluated. Also, the resin composition pellets are supplied to an injection molding machine (EC-100, manufactured by Toshiba Machine), melted at a cylinder temperature of 210 ° C., injection pressure 50%, injection pressure 60%, mold temperature 15 ° C., cooling. Injection molding was performed at a time of 15 seconds to prepare 0.8 mm bending test pieces, and the moldability and flame retardancy were evaluated.
Next, the obtained resin composition pellets are supplied to a biaxial kneaded extrusion foam production apparatus (PCM-45 extrusion foaming apparatus), melted at a temperature of 200 ° C., a cooling zone of 165 ° C., a screw rotation speed of 75 rpm, A foam sheet having a thickness of 1.0 to 2.0 mm made of closed cells was prepared by adding 1.2% by mass of carbon dioxide under a discharge rate of 25 kg / h. The results are shown in Table 1.
Further, the resin compositions obtained in Examples 2, 6, 10, 13, and 17 were freeze pulverized to produce particles having an average particle diameter of 1 mm. After drying these particles, n-butane / iso-butane (20/80 mass ratio) mixed gas was used as a blowing agent, and a batch foaming test (using a pressure vessel, butane mixed gas at 150 ° C. × 10 MPa × 2 hr. After impregnation, foaming (returning to normal pressure) was performed at 120 ° C. The expansion ratio of the obtained expanded particles is shown in Table 2.

In Examples 1-4, the kind and bromide type flame retardant (E1) shown in Table 1 were added as the flame retardant (E). All brominated flame retardants (E1) had the same tendency. When the addition amount was 8 parts by mass, A rank flame retardancy was obtained and foamability was good. When the addition amount was increased to 20 parts, the foamability was slightly lowered, but V-0 flame retardancy was obtained.
In Examples 5-8, the kind shown in Table 1 and a mass part phosphorus flame retardant (E2) were added as a flame retardant (E). The results are the same as for the brominated flame retardant (E1). When the amount added is 8 parts by mass, the flame retardancy is A rank, and a good foam is obtained. When the amount added is 20 parts by mass, the foamability is reduced. Flame retardancy of −0 and V-2 was obtained.
In Examples 9 and 10, as a flame retardant (E), a part by mass of camphor sulfonic acid shown in Table 1 was added. When the added amount was 0.5 parts by mass, the flame retardancy was V-2, but when it was 1.0 parts by mass, the flame retardancy of V-0 was obtained. When the addition amount was 1.0 part by mass, the foamability was slightly lowered.
In Examples 11 to 16, as the flame retardant (E), two types of flame retardants (E2) having the types shown in Table 1 and parts by mass were added. The flame retardancy was V-0 and V-2, and the foamability was also good.

In Examples 18-20, 3 types of flame retardants were used as a flame retardant (E), and the epoxy group containing chain extender (D) of the mass part shown in Table 1 was added. As the amount of the epoxy group-containing chain extender (D) added increased, the foamability improved and the expansion ratio increased. All flame retardancy was V-0.
In Examples 21 to 23, three types of flame retardants were used as the flame retardant (E), and the types and parts by mass of the (meth) acrylic acid ester compound (B) and organic peroxide (C) shown in Table 1 Was added. All the flame retardancy was as good as V-0, and the foamability was almost unchanged.

  In Examples 24-29, the biodegradable polyester resin (A) of the type shown in Table 1 was used. When polylactic acid is used as the biodegradable polyester resin (A), the heat resistance decreases as the D% increases, but the flame retardancy is V-0 and V-2, and the foamability is also good. Met.

  The expanded particles obtained in Examples 2, 6, 10, 13, and 17 were extremely uniform, the expansion ratio was 7 to 14 times, and were composed of independent bubbles.

In Comparative Examples 1 and 5, the foamability was very good. However, the flame retardant (E) was not blended or the blending amount was small, so the fired flame did not extinguish and was NG.
In Comparative Examples 2 to 4, the amount of the flame retardant (E) is large, and since the epoxy group-containing chain extender (D) is not blended, the MFR increases, the melt viscosity and the melt tension decrease, and the foaming property is low. It was greatly reduced.
In Comparative Examples 6 and 7, since the (meth) acrylic ester compound (B) was not blended or the blending amount was small, the melt viscosity was improved, but the foamability was not improved.
In Comparative Examples 9 and 10, since the organic peroxide (C) was not blended or the blending amount was small, the melt viscosity was low and the foamability was low.
In Comparative Examples 8 and 11, since a large amount of the (meth) acrylic acid ester compound (B) and the organic peroxide (C) was blended, the melt viscosity was high and foam molding was impossible.
In Comparative Example 12, since the epoxy group-containing chain extender (D) was not blended, the melt viscosity was low and the foamability was lowered.
In Comparative Examples 13 to 15, since a large amount of the epoxy group-containing chain extender (D) was blended, the melt viscosity was high and foam molding was impossible.

It is a schematic diagram of the degree of crystallinity (θ) and time when obtaining the velocity index.

Claims (7)

  Biodegradable polyester resin (A) 100 parts by mass, (meth) acrylic acid ester compound (B) 0.01-10 parts by mass, organic peroxide (C) 0.01-10 parts by mass, epoxy group A resin composition obtained by melt-kneading 0.1 to 1.4 parts by mass of a chain extender (D) and 0.1 to 21 parts by mass of a flame retardant (E), which is a biodegradable polyester resin ( A) is a resin containing 70 mol% or more of α- and / or β-hydroxycarboxylic acid units, and the flame retardant (E) is a brominated flame retardant (E1) and / or a phosphorus flame retardant (E2). And / or a resin composition for foaming a biodegradable flame retardant polyester, which is camphorsulfonic acid (E3).   The amount of the brominated flame retardant (E1) is 3 to 20 parts by mass and the amount of the phosphorus flame retardant (E2) is 3 to 20 parts by mass with respect to 100 parts by mass of the biodegradable polyester resin (A). The compounding quantity of camphor sulfonic acid (E3) is 0.1-1.0 mass part, The resin composition of Claim 1 characterized by the above-mentioned.   The (meth) acrylic acid ester compound (B) has two or more (meth) acryl groups in the molecule, or one or more (meth) acryl groups and one or more glycidyl groups or vinyl groups. The resin composition according to claim 1, wherein the resin composition is a compound.   The resin composition according to claim 1, wherein the α- and / or β-hydroxycarboxylic acid unit is D-lactic acid, L-lactic acid, or a mixture thereof.   The resin composition according to any one of claims 1 to 4, wherein the crystallization rate index of the resin composition is 10 (min) or less.   A biodegradable flame retardant polyester resin foam obtained by foam-molding the resin composition according to claim 1.   A biodegradable flame retardant polyester resin molded article obtained by molding the foam according to claim 6.