JP2609795B2 - Polyester expandable particles and foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an expandable foam having excellent thermal stability and mechanical strength using an aliphatic polyester having biodegradability, a practically sufficient high molecular weight and specific melting characteristics. It relates to particles and foams.

[0002]

2. Description of the Related Art In recent years, foams are often formed by adding a volatile foaming agent to form expandable particles. However, these particles are liable to fluctuate in the content of the foaming agent, are easily soiled, and cannot be used for molding. Often. The waste of plastics used in large quantities has the potential to contaminate rivers, oceans, and soil, and has become a major social problem. To prevent this pollution, the emergence of biodegradable plastics has been increasing. For example, poly (3-hydroxybutyrate) produced by a fermentation method using a microorganism, and a blend of starch, which is a natural polymer of a blend system, and a general-purpose plastic have been long-awaited. However, the former has a drawback in that since the thermal decomposition temperature of the polymer is close to the melting point, the molding processability is inferior, and microorganisms create the raw material unit, which is very poor.
In the latter, since the natural polymer itself is not thermoplastic, there is a difficulty in moldability, and the use range is greatly restricted.
On the other hand, although aliphatic polyesters are known to have biodegradability, they have hardly been used because a high molecular weight product sufficient for obtaining practical molded article properties cannot be obtained. Recently, ε-caprolactone has been found to have a high molecular weight by ring-opening polymerization, and has been proposed as a biodegradable resin. However, the melting point is as low as 62 ° C. ing. Glycolic acid and lactic acid also have high molecular weights obtained by ring-opening polymerization of glycolide and lactide, and are slightly used for medical fibers, etc. It has not been used in large quantities in the body.

[0003] Styrene polymer particles containing 0.5 to 40 parts by weight of a readily volatile blowing agent such as propane, butane, pentane, methyl chloride, and dichlorofluoromethane are known as expandable styrene polymer particles. ing. Also,
When the expandable styrene polymer particles are heated above the softening point, they become pre-expanded particles in which a number of small bubbles are generated. The pre-expanded particles are filled into a closed mold cavity in the shape of a final product having a number of small holes formed in a wall surface, and a heating medium, such as water vapor, is sprayed on the particles through the small holes to form the particles. A method is known in which each of the particles is heated to a temperature equal to or higher than the softening point thereof to foam the respective particles and welded to each other to produce a porous styrene polymer foam according to the mold cavity. Usually, polystyrene is used for molding the expandable particles, and high-molecular-weight polyester used for general packaging (here, high-molecular-weight polyester refers to those having a number average molecular weight of 10,000 or more) Even polyethylene terephthalate, which is a condensate of terephthalic acid (including dimethyl terephthalate) and ethylene glycol, has not been used in this field, and attempts to impart biodegradability have not yet been reported. It is not at present. Therefore, it can be said that there is no idea that foamable particles are formed by using a biodegradable aliphatic polyester using an aliphatic type dicarboxylic acid as a conventional dicarboxylic acid and put to practical use. One of the reasons why the idea of this practical use has not been born is that, despite the fact that the foam particles are required to have special production conditions and physical properties, even if they are crystalline, the aliphatic polyester Most of the polyesters have a melting point of 100 ° C. or less, and furthermore, have poor thermal stability at the time of melting, and more importantly, the properties of this aliphatic polyester, particularly the mechanical properties represented by tensile strength. However, even at the same level of the number average molecular weight as the above polyethylene terephthalate, the compound showed a remarkably inferior value. Further, it is inferred that one of the reasons is that the study for further improving the physical properties by further increasing the number average molecular weight of the aliphatic polyester has not sufficiently progressed due to poor thermal stability.

[0004]

SUMMARY OF THE INVENTION The present invention uses these aliphatic polyesters as components, has a practically sufficient high molecular weight, and is excellent in mechanical properties represented by thermal stability and tensile strength. Another object of the present invention is to provide a foamable particle which is biodegradable as one of disposal means, that is, a foam which can be decomposed by microorganisms or the like and which can be easily disposed after use.

[0005]

Means for Solving the Problems The present inventors have studied various reaction conditions for obtaining a polyester which gives expandable particles having a high molecular weight and sufficient practicality, and as a result, while maintaining biodegradability. A specific aliphatic polyester having a practically sufficient high molecular weight is obtained, and a foam molded using the expandable particles produced therefrom has not only the above biodegradability, but also thermal stability and mechanical strength. And found that the present invention was completed.

That is, the gist of the present invention is as follows.
° C, the melt viscosity at a shear rate of 100 sec ^-1 is 1.0
× 10 ^{3 to} 1.0 × 10 ⁶ poise, with a melting point of 70 to
100 parts by weight of aliphatic polyester particles at 190 ° C.
Foamable particles consisting of 0.5 to 40 parts by weight of a volatile foaming agent,
(B) The aliphatic polyester has a number average molecular weight of 10,000
(A) the expandable particles containing urethane bonds of 0.03 to 3.0% by weight, and (C) the number average molecular weight is 5,0
100 parts by weight of an aliphatic polyester prepolymer having a melting point of 60 ° C. or more, 100 parts by weight of an aliphatic polyester obtained by reacting 0.1 to 5 parts by weight of a diisocyanate with a volatile foaming agent. 5 to 40 parts by weight of the expandable particles (A) or (B). Further, the present invention provides a foam such as a cold box or a cushion by prefoaming the above expandable particles and expanding the foam in a mold. Hereinafter, the contents of the present invention will be described in detail.

The aliphatic polyester referred to in the present invention is a trifunctional or tetrafunctional polyfunctional component comprising a glycol and a dicarboxylic acid (or an acid anhydride thereof) as two components or, if necessary, a third component. A polyester obtained by adding and reacting at least one polyfunctional component selected from a polyhydric alcohol, an oxycarboxylic acid and a polycarboxylic acid (or an acid anhydride thereof) as a main component; A polyester prepolymer having a relatively high molecular weight and having a hydroxyl group is prepared, and this is further increased in molecular weight by a coupling agent.

Conventionally, a low molecular weight polyester prepolymer having a number average molecular weight of 2,000 to 2,500 having a hydroxyl group as a terminal group is reacted with a diisocyanate as a coupling agent to form a polyurethane, Foams, paints and adhesives are widely used. However, polyester prepolymers used for these polyurethane foams, paints and adhesives are:
The maximum number average molecular weight that can be synthesized without a catalyst is 2,0
It is a low molecular weight prepolymer of 100 to 2,500, and in order to obtain practical physical properties as a polyurethane with respect to 100 parts by weight of the low molecular weight prepolymer, the amount of diisocyanate used is 10 to 20 parts by weight. When such a large amount of diisocyanate is added to a low-molecular-weight polyester melted at 150 ° C. or higher, gelation occurs and a normal melt-moldable resin cannot be obtained.
Accordingly, a polyester obtained by using such a low molecular weight polyester prepolymer as a raw material and reacting a large amount of diisocyanate cannot be used as the raw material for expandable particles of the present invention.

As in the case of polyurethane rubber, a method of converting a hydroxyl group into an isocyanate group by adding a diisocyanate and further increasing the number average molecular weight with a glycol may be considered. As described above, the amount is 10 parts by weight or more based on 100 parts by weight of the prepolymer, so that practical properties are obtained. If a polyester prepolymer having a relatively high molecular weight is to be used, the heavy metal catalyst required for the synthesis of the prepolymer significantly promotes the reactivity of the isocyanate group used in the above amount, resulting in poor storage stability, crosslinking reaction, and branching. Since it is not preferable to use a polyester prepolymer synthesized without a catalyst as a polyester prepolymer, the number average molecular weight is limited to about 2,500 at the highest even if it is high.

The polyester prepolymer for obtaining the aliphatic polyester used in the present invention has a terminal group substantially having a hydroxyl group and a number average molecular weight of 5,000.
A saturated aliphatic polyester having a relatively high molecular weight of 0 or more, preferably 10,000 or more, and a melting point of 60 ° C. or more, which is obtained by catalyzing a glycol with an aliphatic dicarboxylic acid (or an anhydride thereof). can get. When the number average molecular weight is less than 5,000, for example, about 2,500, a small amount of coupling agent of 0.1 to 5 parts by weight used in the present invention can provide a polyester for expandable particles having good physical properties. Can not do. Number average molecular weight is 5,000
The above polyester prepolymer has a hydroxyl value of 30 or less, and is free from a gel during the reaction because it is not affected by the remaining catalyst even under severe conditions such as a molten state by using a small amount of a coupling agent. , A high molecular weight polyester can be synthesized.

That is, the aliphatic polyester used in the present invention is a polyester prepolymer composed of an aliphatic glycol and an aliphatic dicarboxylic acid and having a number average molecular weight (Mn) of 5,000 or more, preferably 10,000 or more, for example, a cup. It has a structure linked via a urethane bond derived from diisocyanate as a ring agent. Furthermore, in the aliphatic polyester used in the present invention, the polyester prepolymer has a long-chain branch derived from a polyfunctional component, and this is, for example, via a urethane bond derived from diisocyanate as a coupling agent. It has a chained structure. When an oxazoline, a diepoxy compound, or an acid anhydride is used as a coupling agent, the polyester prepolymer takes a chain structure via an ester bond.

The glycols used include, for example, ethylene glycol, 1,4-butanediol, 1,6
-Hexanediol, decamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol and the like. Ethylene oxide can also be used. These glycols may be used in combination.

Aliphatic dicarboxylic acids (or acid anhydrides thereof) which react with glycols to form aliphatic polyesters include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, succinic anhydride, and succinic anhydride. Adipic acid and the like are generally commercially available and can be used in the present invention. Aliphatic dicarboxylic acids (or their acid anhydrides) may be used in combination.

(Third component) In addition to these glycols and dicarboxylic acids, if necessary, as a third component, a trifunctional or tetrafunctional polyhydric alcohol, oxycarboxylic acid and polycarboxylic acid ( Or its acid anhydride)
And at least one kind of polyfunctional component selected from the above may be reacted. By adding this third component, long-chain branching occurs in the molecule, so that the molecular weight is increased and Mw is increased.
/ Mn increases, that is, the molecular weight distribution increases,
Desirable properties can be imparted to foam molding and the like. The amount of the polyfunctional component to be added is 0.1 in the case of trifunctional with respect to 100 mol% of all components of the aliphatic dicarboxylic acid (or an acid anhydride thereof) so that there is no danger of gelling. It is 1 to 5 mol%, and in the case of tetrafunctional, it is 0.1 to 3 mol%.

(Polyfunctional Component) Examples of the polyfunctional component used as the third component include trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids. The trifunctional polyhydric alcohol component is typically trimethylolpropane, glycerin or its anhydride, and the tetrafunctional polyhydric alcohol component is pentaerythritol.

The trifunctional oxycarboxylic acid component comprises (i)
There are two types of carboxyl groups and one hydroxyl group in the same molecule, and (ii) a type having one carboxyl group and two hydroxyl groups. In terms of being available at
Malic acid which shares two carboxyl groups and one hydroxyl group in the same molecule of (i) is practically advantageous and sufficient for the purpose of the present invention. There are the following three types of tetrafunctional oxycarboxylic acid components. That is, (i)
A type sharing three carboxyl groups and one hydroxyl group in the same molecule, (ii) a type sharing two carboxyl groups and two hydroxyl groups in the same molecule, (iii) three types There is a type in which a hydroxyl group and one carboxyl group are shared in the same molecule, and any type can be used. However, from the viewpoint that a commercially available product can be easily obtained at low cost, citric acid In addition, tartaric acid is practically advantageous and is sufficient for the purpose of the present invention.

As the trifunctional polycarboxylic acid (or an acid anhydride thereof) component, for example, trimesic acid, propanetricarboxylic acid or the like can be used, but trimellitic anhydride is advantageous from a practical viewpoint. Is sufficient for the purpose. Tetrafunctional polycarboxylic acid (or its acid anhydride)
There are various types such as aliphatic, cycloaliphatic, and aromatic in the literature, but from the viewpoint that commercially available products can be easily obtained, for example, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, cyclopentane Tetracarboxylic anhydrides are mentioned and are sufficient for the purposes of the present invention.

These glycols and aliphatic dicarboxylic acids are mainly composed of aliphatic compounds, but may be used in combination with a small amount of other components such as aromatic compounds. However, if other components are introduced, the biodegradability deteriorates, so the content is 20% by weight or less, preferably 10% by weight or less, more preferably 5% by weight or less.

The polyester prepolymer for aliphatic polyester used in the present invention has a terminal group substantially a hydroxyl group. For that purpose, glycols and aliphatic dicarboxylic acids (or acid anhydrides thereof) used in the synthesis reaction are used. ) Requires the use of glycols in some excess.

In order to synthesize a polyester prepolymer having a relatively high molecular weight, it is necessary to use a deglycol-reaction catalyst during the deglycolization reaction following the esterification. Examples of the deglycol-reaction catalyst include titanium compounds such as acetoacetoyl-type titanium chelate compounds and organic alkoxytitanium compounds. These titanium compounds can be used in combination. Examples of these include diacetacetoxyoxytitanium ("Narcem Titanium" manufactured by Nippon Chemical Industry Co., Ltd.), tetraethoxytitanium, tetrapropoxytitanium, tetrabutoxytitanium and the like. The use ratio of the titanium compound is 0.001 to 1 with respect to 100 parts by weight of the polyester prepolymer.
Parts by weight, desirably 0.01 to 0.1 parts by weight. The titanium compound may be added from the beginning of the esterification, or may be added immediately before the deglycolization reaction.

Further, the number average molecular weight is 5,000 or more,
Desirably, a coupling agent is used to further increase the number average molecular weight of the polyester prepolymer in which 10,000 or more terminal groups are substantially hydroxyl groups. Examples of the coupling agent include diisocyanates, oxazolines, diepoxy compounds, acid anhydrides, and the like.
Particularly, diisocyanate is preferable. In the case of an oxazoline or diepoxy compound, it is necessary to react a hydroxyl group with an acid anhydride or the like and convert the terminal to a carboxyl group before using a coupling agent. The type of diisocyanate is not particularly limited.
4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-
Naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate,
In particular, hexamethylene diisocyanate is preferred in terms of the hue of the formed resin, the reactivity when adding polyester, and the like.

The amount of the coupling agent to be added is 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the polyester prepolymer. If the amount is less than 0.1 part by weight, the coupling reaction is insufficient. If the amount exceeds 5 parts by weight, gelation is liable to occur.

The addition is desirably carried out under conditions in which the polyester prepolymer is in a uniform molten state and can be easily stirred. It is not impossible to add to the solid polyester prepolymer and melt and mix through an extruder, but it is added to the aliphatic polyester production equipment or to the molten polyester prepolymer (for example, in a kneader). It is practical to do.

The aliphatic polyester used in the present invention is required to have a specific melting property in order to be foamed with a volatile foaming agent. That is, temperature 190 ° C., shear rate 1
The melt viscosity at 00 sec ^-1 is 1.0 × 10 ^{3 -1} .
0 × 10 ⁶ poise, preferably 5.0 × 10 ³ to
5.0 × 10 ⁵ poise, 7.0 × 10 ^{3 to} 1.0 × 10
⁵ poise is particularly preferred. If the viscosity is less than 1.0 × 10 ³ poise, bubbles cannot be formed because the viscosity is too low.
Above ¹⁰⁶ poise when not grow air bubbles because the viscosity is too high, not become a practical foam. The melt viscosity was measured at a shear rate of 100 sec ^-1 from a graph of the relationship between the shear rate measured at a resin temperature of 190 ° C. and the apparent viscosity using a nozzle having a nozzle diameter of 1.0 mm and a nozzle of L / D = 10. The viscosity was determined.

Further, the melting point of the aliphatic polyester used in the present invention needs to be 70 to 190 ° C, more preferably 70 to 150 ° C, and particularly preferably 80 to 135 ° C. If it is lower than 70 ° C., the heat resistance is insufficient, and if it is higher than 190 ° C., it is difficult to manufacture.
In order to obtain a melting point of 70 ° C. or more, the melting point of the polyester prepolymer needs to be 60 ° C. or more.

When the aliphatic polyester used in the present invention contains a urethane bond, the amount of the urethane bond is 0.03 to 3.0% by weight, preferably 0.05 to 2.0% by weight, 0.1 to 1.0% by weight is particularly preferred. The urethane bond amount is measured by C ₁₃ NMR and agrees well with the charged amount. When the amount is less than 0.3% by weight, the effect of increasing the molecular weight by urethane bonds is small, and the moldability is poor. When the amount exceeds 3.0% by weight, a gel is generated.

The average radius of the aliphatic polyester particles for producing the expandable particles according to the present invention is 0.05 mm to 10 mm.
mm, more preferably 0.2 to 6 mm,
Most preferably, it is 0.3 to 3 mm. When the particle radius is less than 0.05 mm, the inside of the mold is too densely packed with the particles, so that the inside is insufficiently heated. On the other hand, if it exceeds 10 mm, the appearance is deteriorated because the particles are not sufficiently filled in the mold.

The heat of combustion (JIS M8814) of the aliphatic polyester for expandable particles according to the present invention is 7000.
cal / kg or less, which is lower than polyethylene or polypropylene, and is easy to incinerate. This means
This is advantageous when the aliphatic polyester is incinerated without being treated by the biodegradation method.

When the above-mentioned aliphatic polyester is used for producing the expandable particles according to the present invention, a lubricant, a wax, a coloring agent, etc. may be used in addition to an antioxidant, a heat stabilizer, an ultraviolet absorber and the like, if necessary. Of course, an agent, a crystallization accelerator and the like can be used in combination. That is, as an antioxidant, p
Hindered phenolic antioxidants such as -tbutylhydroxytoluene, ptbutylhydroxyanisole,
Examples of heat stabilizers such as sulfur antioxidants such as distearyl thiodipropionate and dilauryl thiodipropionate, and heat stabilizers such as triphenyl phosphite, trilauryl phosphite, and trisnonyl phenyl phosphite; , Pt-butylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2
-Hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, etc., as lubricants, calcium stearate, zinc stearate, barium stearate, sodium palmitate, etc., as antistatic agents, N, N-bis (hydroxyethyl) alkylamine, alkylamine, alkylallyl sulfonate, alkyl sulfonate, etc., as a flame retardant, hexabromocyclododecane, tris-
(2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, etc., inorganic fillers or foam nucleating agents such as calcium carbonate, silica, titanium oxide, talc, mica, barium sulfate, alumina, etc. , Polyethylene terephthalate, poly-trans cyclohexane dimethanol terephthalate and the like.

The volatile blowing agent used in the present invention needs to have a boiling point below the melting point of the aliphatic polyester, which does not dissolve or only slightly swells the aliphatic polyester. When the volatile foaming agent has a boiling point higher than the melting point of the resin or dissolves, since the resin is completely melted or dissolved and then volatilized, uniform and fine bubbles cannot be obtained. Examples of such volatile foaming agents include aliphatic hydrocarbons such as propane, butane, pentane, isobutane, neopentane, isopentane, hexane, and butadiene, as well as methyl chloride, methylene chloride, dichlorofluoromethane, chlorotrifluoromethane, and dichloromethane. Halogenated hydrocarbons such as difluoromethane, chlorodifluoromethane, and trichlorofluoromethane;

The volatile blowing agent is used in an amount of 0.5 to 40 parts by weight based on 100 parts by weight of the polyester particles. 0.5
If the amount is less than the weight part, a foam having a sufficient expansion ratio cannot be obtained,
It is difficult to use in excess of 40 parts by weight in terms of molding, and even if it can be used, the bubbles become coarse and cannot be put to practical use.

The effervescent particles can be produced by suspending fatty acid polyester particles in water, pressing a volatile effervescent agent with stirring, and heating. When the expandable particles of the present invention are pre-expanded at an expansion ratio of 5 times or more and then molded, a foamed product having a high expansion ratio can be manufactured.

The expandable particles of the present invention are expanded to a foaming ratio of 5 times or more by heating steam, filled in a mold after drying and aging, and further heated with steam to obtain a high foaming ratio according to the mold. A foamed product can be obtained, and the use thereof is useful for a food container such as a cup ramen, a cushioning material for use in transporting a television, a stereo, or the like, a fish box, and a foam such as a heat insulation or cold insulation box.

The insulated box in the present invention is a box used for transporting and storing foods, beverages, medical supplies, etc., particularly fish, meat and vegetables in a refrigerated or frozen state. It is a box made of a material that keeps heat insulation so that it does not rise. The cool box consists of only a box for storing the contents, or a box and a lid covering the upper part thereof. One of the most important characteristics for use as a cool box is that the material constituting the cool box has high heat insulation. Here, the cool box includes what is generally called a cool box having a function of preventing a decrease in the temperature of the contents.

In the method for producing the cool box of the present invention, generally, a high-molecular-weight aliphatic polyester is melt-extruded into particles, which are impregnated with a volatile blowing agent to form expandable polyester particles. Is heated with steam (about 100-1
10 ° C.) to produce pre-expanded particles of 5 to 20 times. Further, the particles are placed in a mold for forming a cool box, and heated and foamed to form a cool box.

The cold box obtained in the present invention is easily decomposed by microorganisms and the like, has excellent heat insulation properties, and has practically sufficient mechanical properties. The thermal conductivity used as practical physical properties of the cool box is measured in accordance with JIS A-1412, and needs to be 0.1 (kcal / mh ° C) or less, and 0.08 (kcal / mh ° C). The following is preferable, and 0.06 (kcal / mh ° C) or less is preferable.
If it exceeds 0.1 (kcal / mh ° C.), for example, the freshness of fish, which is an important role as a cool box, is not sufficiently maintained, which is not preferable in practical use.

The cushioning material in the present invention includes electrical equipment such as televisions and radios, precision equipment such as computers and watches, optical equipment such as glasses and microscopes, other glass products,
When transporting and storing products such as ceramics, it is a cushioning material used to soften external shocks and prevent the products from breaking down or being damaged. The cushioning material is used for packing the product only with the cushioning material or for being placed between the packaging material such as a cardboard box and the product.

The method for producing the cushioning material of the present invention includes extrusion or injection molding without using particles, but impregnated with a volatile foaming agent and converting it into pre-expanded particles 5 to 20 times with heated steam. Further, a method in which the particles are heated and foamed in a mold having a predetermined shape may be used.

The buffering material obtained in the present invention not only has a lower calorific value during combustion than PS, is easily decomposed by microorganisms and the like, has excellent creep properties, and has practically sufficient mechanical properties. The creep characteristic used as a practical property of the cushioning material is represented by a compression creep measured after a load of 0.1 kg / cm ² and 24 hours in accordance with JIS K-6767. The compression creep of the cushioning material obtained in the present invention needs to be 15% or less.
It is preferably at most 2%, more preferably at most 10%. 15%
If it exceeds, the amount of deformation is large when stress is applied from the outside when used as a cushioning material, and the recovery is small, which is not preferable in practical use. That is, the breakage rate of various electronic devices during transportation increases.

[0040]

The present invention will be described below with reference to examples and comparative examples.

Example 1 A 700 L reactor was purged with nitrogen and charged with 183 kg of 1,4-butanediol and 224 kg of succinic acid. Raise the temperature under a nitrogen stream and
3.5 hours at 92-220 ° C.
The esterification reaction by dehydration condensation was performed for 3.5 hours under reduced pressure of 0 to 2 mmHg. The collected sample is
The acid value is 9.2 mg / g, and the number average molecular weight (Mn) is 5.1.
60 and the weight average molecular weight (Mw) was 10,670. Subsequently, 34 g of tetraisopropoxy titanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature,
A deglycol-reaction was performed at a temperature of 215 to 220 ° C. under a reduced pressure of 15 to 0.2 mmHg for 5.5 hours. The collected sample had a number average molecular weight (Mn) of 16,800 and a weight average molecular weight (Mw) of 43,600. The yield of this polyester (A1) is 339 k excluding condensed water.
g.

5.42 kg of hexamethylene diisocyanate was added to a reactor containing 339 kg of polyester (A1), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.70 kg (manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added.
Stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B1) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B1) is a slightly ivory white wax-like crystal having a melting point of 110.
° C, the number average molecular weight (Mn) is 35,500, the weight average molecular weight (Mw) is 170,000, the MFR (190 ° C) is 1.0 g / 10 min, the viscosity of a 10% solution of orthochlorophenol is 230 poise, Temperature 190 ° C, shear rate 10
The melt viscosity at ⁰ sec ^-1 was 1.5 × 10 ⁴ poise. The average molecular weight is measured by Shodex GPC
System-11 (Showa Denko KK gel chromatography), solvent of CF ₃ COONa HFIPA5m
mol solution, concentration 0.1 wt%, calibration curve is Showa Denko KK PMMA standard sample ShodexStand
ard M-75.

Into an autoclave with a stirrer having an inner volume of 5.6 L, 2200 g of pure water was placed, 2200 g of polyester (B1) particles, 7 g of magnesium oxide and 0 g of dilauryl thiodipropionate, which were between 28 mesh and 35 mesh according to the Tyler standard. .22 g was charged. Then, while stirring, 44 g of propane and 186 g of pentane were injected and the temperature was raised to 100 ° C. and reacted for 1.5 hours. Then, the temperature in the system was cooled to 30 ° C., and the polyester (B1) was taken out from the system. )) Was obtained. The obtained expandable particles were expanded 10 times by heating of steam to obtain pre-expanded particles. After drying and aging these pre-expanded particles,
It was filled into a cup-shaped mold having a thickness of 3.0 mm, and was heated and formed by steam. When the obtained expandable particles of the polyester (B1) were expanded 50 times, the distribution width of the bubble size was 0.08 to 0.30 mm. The calorific value of combustion was 5,720 kcal / kg. When the expandable particles were buried in the soil for 5 months, not only the expandability but also the shape of the particles were lost, and a change in decomposition was observed.

Example 2 A 700 L reactor was purged with nitrogen and charged with 177 kg of 1,4-butanediol, 198 kg of succinic acid, and 25 kg of adipic acid. The temperature was raised under a nitrogen stream, and the temperature was increased to 190 to 210 ° C. for 3.5 hours.
2. Further stop nitrogen, and under a reduced pressure of 20 to 2 mmHg.
The esterification reaction by dehydration condensation was performed for 5 hours. The collected sample had an acid value of 9.6 mg / g, a number average molecular weight (Mn) of 6,100, and a weight average molecular weight (M
w) was 12,200. Subsequently, 20 g of a catalyst, tetraisopropoxytitanium, was added under a nitrogen stream at normal pressure. Raise the temperature, 15 ~
The glycol removal reaction was performed under a reduced pressure of 0.2 mmHg for 6.5 hours. The collected sample is number average molecular weight (Mn)
Is 17,300, and the weight average molecular weight (Mw) is 46,
400. The yield of this polyester (A2) was 337 kg excluding condensed water.

4.66 kg of hexamethylene diisocyanate was added to a reactor containing 333 kg of polyester (A2), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.70 kg (manufactured by Ciba Geigy) and 1.70 kg of calcium stearate as a lubricant were added.
Stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B2) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B2) was a slightly ivory white wax-like crystal having a melting point of 103.
° C, number average molecular weight (Mn) is 36,000, weight average molecular weight (Mw) is 200,900, MFR (190 ° C) is 0.52 g / 10 min, and 10% of orthochlorophenol.
The solution has a viscosity of 680 poise, a temperature of 190 ° C. and a shear rate of 1.
The melt viscosity at 00 sec ^-1 was 2.2 × 10 ⁴ poise.

Into an autoclave with a stirrer having an inner volume of 5.6 L, 2200 g of pure water was put, and 2,200 g of polyester (B2) particles and 0.6 g of sodium dodecylbenzenesulfonate between 9 mesh and 12 mesh according to Tyler standard were added. I put it in. Then, with stirring, propane 4
4 g and 186 g of pentane were press-fitted, heated to 100 ° C. and reacted for 6 hours. Then, the temperature in the system was cooled to 30 ° C., followed by dehydration and drying to obtain expandable particles of polyester (B2). Was. After the obtained particles were stored at 10 ° C. for 2 weeks, those foamed 10 times with steam were used as pre-expanded particles. After leaving the pre-expanded particles for 24 hours, they are filled in a mold having a mold size of 300 mm × 400 mm × 100 mm,
Heat molding was performed using steam. When the obtained polyester (B2) is foamed 50 times, the distribution width of cell size is 0.1 to 0.35 mm, and the average cell size is 0.1 to 0.35 mm.
2 mm. When the expandable particles were buried in the soil for 5 months, the same results as in Example 1 were obtained.

(Example 3) After replacing a 700 L reactor with nitrogen, 200 kg of 1,4-butanediol, 250 kg of succinic acid and 2.8 kg of trimethylolpropane were used.
Was charged. The temperature was raised under a nitrogen stream,
At 4.5 ° C. for 4.5 hours, and further stop nitrogen for 20 to 2 mmH.
The esterification reaction by dehydration condensation was performed under reduced pressure of 5.5 g for 5.5 hours. The collected sample has an acid value of 10.
The number average molecular weight (Mn) was 4,900, and the weight average molecular weight (Mw) was 10,000. Subsequently, 37 g of tetraisopropoxytitanium as a catalyst was added under a nitrogen stream at normal pressure. Raise the temperature to 210
8.0 to 220 ° C. under reduced pressure of 15 to 1.0 mmHg.
The deglycol reaction was performed for a time. The collected sample had a number average molecular weight (Mn) of 16,900 and a weight average molecular weight (Mw) of 90,300 (Mw / Mn = 5.
4). This polyester (A3) is theoretically condensed water 7
Excluding 6 kg, the yield was 367 kg.

3.67 kg of hexamethylene diisocyanate was added to a reactor containing 367 kg of polyester (A3), and a coupling reaction was carried out at 160 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
367 g (manufactured by Ciba-Geigy) and 367 g of calcium stearate as a lubricant were added, and the mixture was further added with 30 g.
Stirring was continued for minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B3) after vacuum drying at 90 ° C. for 6 hours was 350 kg.

The obtained polyester (B3) is a slightly ivory white wax-like crystal having a melting point of 110.
° C, the number average molecular weight (Mn) is 17,900, and the weight average molecular weight (Mw) is 161,500 (Mw / Mn = 9.
0), the MFR (190 ° C.) was 0.21 g / 10 min, the temperature was 180 ° C., and the melt viscosity at a shear rate of 100 sec ⁻¹ was 2.0 × 10 ⁴ poise.

Into an autoclave with a stirrer having an inner volume of 5.6 L, 2200 g of pure water was placed, 2,200 g of polyester (B3) particles, and 0.6 g of sodium dodecylbenzenesulfonate between 9 and 12 mesh according to Tyler standard. Was introduced. Then, with stirring, propane 4
4 g and 186 g of pentane were press-in, heated to 100 ° C. and reacted for 6 hours, and then cooled to 30 ° C. in the system, and then dehydrated and dried to obtain expandable particles of polyester (B3). Was. After the obtained particles were stored at 10 ° C. for 2 weeks, those foamed 10 times with steam were used as pre-expanded particles. After leaving the pre-expanded particles for 24 hours, they are filled in a mold having a mold size of 300 mm × 400 mm × 100 mm,
Heat molding was performed using steam. When the obtained polyester (B3) was foamed 50 times, the distribution width of the cell size was 0.07 to 0.30 mm, and the average cell size was 0.2 mm. When the expandable particles were buried in the soil for 5 months, the same results as in Example 1 were obtained.

Comparative Example 1 Polyester (A1) was molded under the same conditions as in Example 1. However, the cell diameter could not be maintained, and a foam that could withstand practical use was not obtained.

(Example 4) Into an autoclave with a stirrer having an internal volume of 5.6 L, 2200 g of pure water was placed, and the content was between 28 mesh and 35 mesh according to Tyler standard.
2,200 g of the polyester (B1) particles obtained in
7 g of magnesium oxide and 0.22 g of dilauryl thiodipropionate were added. Then, with stirring, 44 g of propane and 186 g of pentane were injected and the temperature was raised to 100 ° C. and reacted for 1.5 hours.
After cooling to 0 ° C, the polyester (B
1) Expandable particles were obtained. The obtained expandable particles were expanded 10 times by heating of steam to obtain pre-expanded particles. After drying and aging the pre-expanded particles, the thickness is 3.0 mm.
Filled in a rectangular mold, and the base is 80 cm with steam
A cold box having a size of 30 cm and a height of 30 cm was formed by heating. The expandable particles of the obtained cool box (1) were expanded 50 times and the average thickness was 1.5 cm. Then JIS
When the thermal conductivity was measured in accordance with A-1412,
0.02 (kcal / mh ° C). When one side of this cool box was buried in the soil for 5 months, its original shape was disassembled and changed to an unrecognizable state.

(Example 5) In the same manner as in Example 4, the particles of the polyester (B2) obtained in Example 2 were prefoamed 10 times, and then a cold box having an expansion ratio of 50 times was formed. When the thermal conductivity of the obtained cool box was measured in the same manner, it was 0.03 (kcal / mh ° C.). In addition,
The calorific value of combustion was 5,850 kcal / kg. When the obtained insulated box was buried in the soil for 5 months, it was decomposed and changed to a box-shaped piece having no practical strength.

Example 6 A 700 L reactor was purged with nitrogen, and then 145 kg of ethylene glycol and succinic acid 2 were added.
51 kg and 4.1 kg of citric acid were charged. The temperature was raised under a nitrogen stream, and the esterification reaction by dehydration condensation was performed at 190 to 210 ° C. for 3.5 hours, and further with the nitrogen stopped, under a reduced pressure of 20 to 2 mmHg for 5.5 hours. The collected sample had an acid value of 8.8 mg / g, a number average molecular weight (Mn) of 6,800, and a weight average molecular weight (Mw) of 13,500. Subsequently, 20 g of a catalyst, tetraisopropoxytitanium, was added under a nitrogen stream at normal pressure.
Raise the temperature to 15-0.2 at a temperature of 210-220 ° C.
The glycol removal reaction was performed under reduced pressure of mmHg for 4.5 hours. The sample collected had a number average molecular weight (Mn) of 3
3,400, and a weight average molecular weight (Mw) of 137,0
00. The yield of this polyester (A4) was 323 kg excluding condensed water.

3.23 kg of hexamethylene diisocyanate was added to a reactor containing 323 kg of polyester (A4), and a coupling reaction was carried out at 180 to 200 ° C. for 1 hour. The viscosity increased rapidly but no gelling occurred. Then, Irganox 1010 was used as an antioxidant.
1.62 kg (manufactured by Ciba-Geigy) and 1.62 kg of calcium stearate as a lubricant were added.
Stirring was continued for another 30 minutes. This reaction product was extruded into water with an extruder and cut into a pellet by a cutter. The yield of the polyester (B4) after vacuum drying at 90 ° C. for 6 hours was 300 kg.

The obtained polyester (B4) is a slightly ivory white wax-like crystal having a melting point of 96 ° C.
The number average molecular weight (Mn) is 54,000, the weight average molecular weight (Mw) is 324,000, and the MFR (190 ° C.) is 1.
1 g / 10 min, viscosity of a 10% solution of orthochlorophenol is 96 poise, temperature 190 ° C., shear rate 100 sec.
The melt viscosity at c ^-1 was 1.6 × 10 ⁴ poise.

In the same manner as in Example 4, the polyester (B
After pre-expanding the particles of 4) to 10 times, the expansion ratio is 50
A double cold box was formed. When the thermal conductivity of the obtained cool box was measured in the same manner, 0.05 (kcal / mh) was obtained.
° C). The calorific value of combustion is 5,850 kcal.
/ Kg. When the obtained cool box was buried in the soil for 5 months, the same results as in Example 5 were obtained.

(Example 7) In the same manner as in Example 4, the particles of the polyester (B3) obtained in Example 3 were pre-expanded 10 times, and then a cold box having an expansion ratio of 50 times was formed. When the thermal conductivity of the obtained cool box was measured in the same manner, it was 0.04 (kcal / mh ° C.). In addition,
The calorific value of combustion was 5,750 kcal / kg. When the obtained cool box was buried in the soil for 5 months, the same results as in Example 5 were obtained.

(Comparative Example 2) Polyester (A1) was molded under the same conditions as in Example 4, but the surface of the molded article had large irregularities, and the cell diameter was coarse and non-uniform (cell diameter 1 mm or more).
Thus, a foam that could be used practically could not be obtained.

(Example 8) Into an autoclave equipped with a stirrer having an internal volume of 5.6 L, 2200 g of pure water was placed, and between 28 mesh and 35 mesh according to Tyler standard, Example 1
2200 g of the polyester (B1) particles obtained in the above, 7 g of magnesium oxide, and 0.22 g of dilauryl thiodipropionate were charged. Then, while stirring, propane (44 g) and pentane (186 g) were injected, and the temperature was raised to 100 ° C., and the reaction was carried out for 1.5 hours.
After cooling to ℃, polyester (B
1) Expandable particles were obtained. The obtained expandable particles were expanded 10 times by heating of steam to obtain pre-expanded particles. After the pre-expanded particles were dried and aged, they were filled into a rectangular mold for transporting a cassette tape recorder, and a buffer box having a base of 20 cm × 15 cm and a height of 8.0 cm was heat-formed with steam. The foamable particles of the obtained box (1) are 50
The foam was doubled, and the average thickness was 1.5 cm. Subsequently, the compression creep was measured in accordance with JIS K-6767 and found to be 13%. Note that the calorific value of combustion was 5,750 kcal / kg. When this plate was buried in soil for 5 months, it became a plate having lost practical strength, and a decomposition change was observed.

(Example 9) In the same manner as in Example 8, the polyester (B2) obtained in Example 2 was prefoamed 10 times, and then a buffer material plate having an expansion ratio of 50 times was formed. . The compression creep of the obtained plate was measured in the same manner and found to be 12%. Further, the calorific value of combustion is 5,850.
kcal / kg. When this plate was buried in the soil for 5 months, it had changed to a state in which the shape retention strength of the plate was lost.

(Example 10) In the same manner as in Example 8, the polyester (B4) obtained in Example 6 was prefoamed 10 times, and then a buffer material plate having an expansion ratio of 50 times was formed. . When the compression creep of the obtained plate was measured in the same manner, it was 11%. When this plate was buried in soil for 5 months, the same results as in Example 8 were obtained.

(Example 11) In the same manner as in Example 8, the polyester (B3) obtained in Example 3 was prefoamed 10 times, and then a buffer material plate having an expansion ratio of 50 times was formed. . The compression creep of the obtained plate was measured in the same manner and found to be 13%. When this plate was buried in soil for 5 months, the same results as in Example 8 were obtained.

(Comparative Example 3) The polyester (A1) obtained in Example 1 was molded under the same conditions as in Example 8, but the surface of the molded article had large irregularities, and the bubble diameter was coarse and non-uniform. With a diameter of 1 mm or more), a foam that could be used practically was not obtained.

[0067]

The expandable particles according to the present invention have biodegradability when buried in soil or the like, and have a lower calorific value even when incinerated than polyethylene or polypropylene. It is also excellent in mechanical strength such as tensile strength and impact strength, and is useful as a food container and the like, and is also used as a cool box, cushioning material and the like.

Continued on the front page (72) Inventor Mitsuhiro Imaizumi 3-2 Chidori-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Showa Denko KK Kawasaki Resin Laboratory (72) Inventor Eiichiro Takiyama 4-12-4 Nishi-Kamakura, Kamakura-shi, Kanagawa

Claims (12)

(57) [Claims] 1. A temperature of 190 ° C. and a shear rate of 100 sec ⁻¹
The composition comprises 100 parts by weight of aliphatic polyester particles having a melt viscosity of 1.0 × 10 ^{3 to} 1.0 × 10 ⁶ poise and a melting point of 70 to 190 ° C., and a volatile foaming agent of 0.5 to 40 parts by weight. Expandable particles. 2. An aliphatic polyester having a number average molecular weight of 1
2. The expandable particle according to claim 1, which has a urethane bond of not less than 000 and 0.03 to 3.0% by weight. 3. 3. An aliphatic obtained by reacting 0.1 to 5 parts by weight of diisocyanate with 100 parts by weight of an aliphatic polyester prepolymer having a number average molecular weight of 5,000 or more and a melting point of 60 ° C. or more. 3. The expandable particles according to claim 1, comprising 100 parts by weight of polyester and 0.5 to 40 parts by weight of a volatile blowing agent. 4. The aliphatic polyester has a number average molecular weight (Mn) comprising an aliphatic glycol and an aliphatic dicarboxylic acid.
The expandable particle according to claim 2 or 3, wherein a polyester prepolymer having a molecular weight of 5,000 or more has a structure linked via a urethane bond. 5. The aliphatic polyester is at least one polyfunctional selected from aliphatic glycols, aliphatic dicarboxylic acids and trifunctional or tetrafunctional polyhydric alcohols, oxycarboxylic acids and polycarboxylic acids or anhydrides thereof. Number average molecular weight (Mn) obtained by adding components and reacting
The expandable particle according to claim 2 or 3, wherein a polyester prepolymer having a molecular weight of 5,000 or more has a structure linked via a urethane bond. 6. The polyester prepolymer is selected from the group consisting of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, decamethylene glycol, neopentyl glycol and 1,4-cyclohexanedimethanol as glycol units. The dicarboxylic acid unit has a unit selected from the group consisting of succinic acid, adipic acid, suberic acid, sebacic acid, dodecanoic acid, succinic anhydride, and adipic anhydride.
Or the expandable particles according to claim 5. 7. The polyester prepolymer contains, as a third component, at least one selected from the group consisting of trimethylolpropane, glycerin and pentaerythritol as a trifunctional or tetrafunctional polyhydric alcohol. 2. The expandable particles according to 1 .. 8. The polyester prepolymer as a trifunctional or tetrafunctional oxycarboxylic acid as a third component,
1 selected from the group consisting of malic acid, citric acid and tartaric acid
The expandable particle according to claim 5, comprising at least one species. 9. The polyester prepolymer is a trifunctional or tetrafunctional polycarboxylic acid as a third component, such as trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride and The expandable particle according to claim 5, comprising one or more members selected from the group consisting of cyclopentanetetracarboxylic anhydride. 10. A temperature of 190 ° C. and a shear rate of 100 sec.
^A cold box or cushioning material formed by heating and foaming an aliphatic polyester having a melt viscosity at ^-1 of 1 × 10 ^{3 to} 1.0 × 10 ⁶ poise and a melting point of 70 to 190 ° C. as a main component. 11. An aliphatic polyester having a number average molecular weight of 1
The insulated box or cushioning material according to claim 10, which has a urethane bond of not less than 000 and 0.03 to 3.0% by weight. 12. A method for producing a cool box or cushioning material, comprising prefoaming the expandable particles according to claim 1 and then subjecting the foamable particles to heat expansion molding in a mold.