JP2907683B2 - Method for producing polyester resin foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester resin foam.

[0002]

2. Description of the Related Art Polyester resins are classified into thermoplastic resins and thermosetting resins. Thermosetting polyester resins are often used together with glass fibers as reinforced plastics, and are rarely used alone. Therefore, the thermosetting polyester resin is not used by foaming only the resin. On the other hand, the thermoplastic polyester resin is often used alone or in a state where another resin is laminated on the resin. Therefore, an attempt was made to foam only this resin into a foam.

The thermoplastic polyester resin is a high-molecular chain polyester obtained by reacting an aromatic dicarboxylic acid with a dihydric alcohol, ie, a diol, that is, by performing an esterification reaction therebetween. Phthalic acid was frequently used as the carboxylic acid, and ethylene glycol was often used as the diol. A typical thermoplastic polyester resin is polyethylene terephthalate. Here, such a crystalline thermoplastic polyester resin is abbreviated as PAT.

Generally, extrusion foaming is the most efficient method for foaming a thermoplastic resin. Therefore, even when PAT is used as a material, an attempt has been made to extrude and foam it to form a foam. However, it was difficult to extrude the PAT into a foam by foaming. This is because PAT is a crystalline resin, and when heated, the melt viscosity sharply decreases near the temperature at which crystals disappear. In other words, it has been said that it is difficult to foam PAT because the temperature range of viscosity suitable for foaming is extremely narrow.

PAT has high mechanical strength and good shape stability, and has excellent heat resistance to withstand 200 ° C. Since PAT is a crystalline resin as described above, molded products having different degrees of crystallinity are produced depending on the molding method. As the degree of crystallinity of the PAT molded body increases, the heat resistance and the rigidity thereof are improved, but the ease of printing, the ease of adhesion, the ease of molding, and the like are reduced. It will be. Conversely, the lower the crystallinity, the more exactly the opposite properties are obtained. Accordingly, attempts have been made to obtain a molded product suitable for the purpose by utilizing the crystallinity.

In order to facilitate PAT foaming, PAT
Attempts have been made to increase the melt viscosity of. For example, JP-A-53-24364 proposes adding a diepoxy compound and calcium stearate or sodium carbonate to PAT. Also, Japanese Unexamined Patent Publication No.
No. 210955 proposes adding a polyfunctional glycidyl ester and a polyfunctional carboxylic acid to PAT. With these proposals, PAT foamed uniformly and finely
Could be obtained. However, it was desired to make the foam more fine.

JP-A-2-251543 discloses a PAT.
As a method of increasing the melt viscosity of PAT, an organic compound having two or more acid anhydride groups in one molecule and a compound of a metal belonging to Group 1, 2, or 3 of the periodic table are added to PAT. Propose that. This proposal makes it easier to foam PAT than many proposals that have been made so far, and that this proposal can provide a PAT foam that is foamed uniformly and finely and at a relatively high magnification. became. However, it has been desired that the foam has a further finer bubble size.

A PAT foam obtained by extrusion foaming often has a sheet shape. In order to make such a sheet-like foam suitable for actual use, it must be further heated and formed into a formed body such as a container. This molding is generally referred to as secondary processing, but the PAT foam sheet produced so far has not had good dimensional stability of the molded article obtained by the secondary processing. That is, when heated to form the foam sheet, the surface of the foam sheet becomes uneven,
Therefore, a molded product obtained by molding the molded product has a bad appearance, or the molded product shrinks greatly when heated slightly. Therefore, it was necessary to improve these properties.

On the other hand, a polyarylate resin is known as a resin similar to PAT. Polyarylate resin (hereinafter abbreviated as AR) is a high molecular weight chain compound obtained by reacting an aromatic dicarboxylic acid with a dihydric phenol. AR is sold by Unitika under the trade name of polyarylate resin or U-polymer. U-
Among the products named polymers, it is said that there is a composition in which AR and PAT are mixed, but the details are not disclosed.

JP-A-53-92661 discloses that a composition is prepared by mixing AR with a polyalkylene phenylene ester, a polyalkylene phenylene ester ether, a polycarbonate, a styrene resin, a polyacrylic acid derivative or a polyamide. doing. Among them, it is described that PAT such as polyethylene terephthalate and polybutylene terephthalate can be used as the polyalkylene phenylene ester. But,
The publication does not state at all about making a foam,
It merely describes that the composition thus obtained is excellent in heat resistance, moldability and the like.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to improve the above-mentioned drawbacks of PAT foam. In other words, it facilitates extrusion foaming, improves the properties of the foamed sheet obtained thereby, improves the secondary workability of the foamed sheet, and improves the dimensional stability of the molded article obtained by the secondary processing. It was done in an attempt.

[0012]

The inventor of the present invention has found that, when a polyarylate resin is mixed with a PAT, it can be easily extruded and foamed, and the foam of the foamed sheet obtained by the extrusion foaming becomes finer, and the secondary It has been found that the secondary foaming ratio increases during processing, and that the shrinkage of the foam during heating decreases. Further, they have found that the glass transition point of the foamed sheet is increased, the tensile strength is also improved, and the performance of the foamed molded product is further improved. The present invention has been made based on such findings.

According to the present invention, in a method for producing a PAT foam by extruding and foaming a foaming agent into PAT, the aromatic dicarboxylic acid is reacted with a dihydric phenol before the foaming agent is incorporated. 1 to 50 parts by weight of the resulting polyarylate resin is added to 99 to 50 parts by weight of the PAT, and an organic compound or diglycidyl phthalate containing two or more acid anhydride groups in one molecule is added.
To 5.0 parts by weight, and 0.02 to 5.0 parts by weight of a metal compound belonging to the first, second or third group of the periodic table.
The present invention relates to a method for producing a PAT foam, characterized by thoroughly mixing them to form a uniform composition, and then extruding the mixture by adding a foaming agent thereto. .

In the present invention, PAT and AR are used as resins. As described above, PAT is obtained by esterifying an aromatic dicarboxylic acid with an aliphatic or alicyclic diol. AR is obtained by reacting an aromatic dicarboxylic acid with a dihydric phenol as described above. The mixing ratio of the two is such that the AR is 1 to 50% by weight based on the PAT of 99 to 50% by weight. The reason is PAT
If the AR exceeds 99% by weight and the AR is less than 1% by weight, the dimensional stability is not significantly improved.
If the AR is less than 50% by weight and the AR exceeds 50% by weight, the secondary workability will not be significantly improved. Among them, PAT is 97-60% by weight and AR is 3-40% by weight.
Preferably, the PAT is 9%.
AR accounts for 5 to 20% by weight and accounts for 5 to 80% by weight.

An aromatic dicarboxylic acid is used to constitute PAT and AR, and various aromatic dicarboxylic acids can be used. Examples include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfondicarboxylic acid, diphenoxyethanedicarboxylic acid, or mixtures or functional derivatives thereof. Of these, terephthalic acid is the most common.

An aliphatic or alicyclic diol is used to constitute the PAT, and various diols can be used as the diol. As the aliphatic diol, for example, ethylene glycol, trimethylene glycol, tetramethylene glycol, neopentylene glycol, hexamethylene glycol, diethylene glycol, or the like can be used, and as the alicyclic diol, cyclohexane dimethanol can be used. They can be used in combination.

Although dihydric phenols are used to constitute AR, various dihydric phenols can be used. For example, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxy-2-methylphenyl) ether, bis (4-hydroxyphenyl)
Sulfone, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2- Screw (4
-Hydroxy-3-methylphenyl) propane, 1,1
-Bis (4-hydroxyphenyl) n-butane, 1,1
-Bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -4'-methylphenylmethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis ( 4-hydroxyphenyl) cyclohexylmethane, 2,2-bis (4-hydroxynaphthyl)
Propane or the like can be used alone or as a mixture.
Among them, 2,2-bis (4-hydroxyphenyl)
Propane or bisphenol A is most widely used.

The most commonly used PATs are polyethylene terephthalate, polybutylene terephthalate, polycyclohexane terephthalate, polyethylene isophthalate, polytrimethylene terephthalate, polytrimethylene isophthalate, polytetramethylene terephthalate, polytetramethylene isophthalate. It is phthalate. Among them, polyethylene terephthalate is preferably used.

The most commonly used ARs are:
It is obtained by reacting terephthalic acid, isophthalic acid or a mixture thereof with bisphenol A.

[0020] Both PAT and AR are hygroscopic resins. Therefore, if the resin is heated without being dried until it is immediately melted, these resins may be hydrolyzed. Therefore, it is preferable that these resins are put into a dehumidifying dryer before being extruded and foamed, and dried while circulating dry air. The dry air is, for example, air having a dew point of −30 ° C. The drying temperature is, for example, 160 ° C., and the time is, for example, 4 to 6 hours.

In the present invention, in order to increase the melt viscosity of PAT, an organic compound containing two or more acid anhydride groups (hereinafter simply referred to as acid anhydride) or diglycidyl phthalate (hereinafter referred to as DGP) ) And a compound of a metal belonging to the first, second, or third group of the periodic table (hereinafter, referred to as a metal compound).

The acid anhydride may be any of aromatic, alicyclic and aliphatic, and may be a halogenated acid anhydride. For example, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, diphenylsulfonetetracarboxylic dianhydride, or the like can be used.
Among them, it is preferable to use pyromellitic anhydride. The acid anhydride is added in an amount of 0.02 to 5.0 parts by weight, more preferably 100 parts by weight, based on 100 parts by weight of the resin.
0.05 to 5 parts by weight with respect to 0 parts by weight.

DGP is

[0024]

Embedded image It is a compound represented by these. The addition amount of this compound is 0.0
The amount is 2 to 5.0 parts by weight, more preferably 0.05 to 5 parts by weight based on 100 parts by weight of PAT.

Various metal compounds can be used. The metal compound may be an organic compound or an inorganic compound. As inorganic compounds, potassium chloride, sodium chloride, sodium hydrogen carbonate, sodium carbonate, potassium carbonate, zinc carbonate, magnesium carbonate, calcium carbonate,
Aluminum carbonate, sodium oxide, potassium oxide, zinc oxide, magnesium oxide, calcium oxide, aluminum oxide, and the like can be used. Further, as the organic compound, sodium stearate, potassium stearate, zinc stearate, magnesium stearate, calcium stearate, aluminum stearate, sodium montanate, calcium montanate, lithium acetate, sodium acetate, zinc acetate, magnesium acetate,
Calcium acetate, sodium caprylate, zinc caprylate, magnesium caprylate, calcium caprylate,
Aluminum caprylate, sodium myristate, zinc myristate, magnesium myristate, calcium myristate, aluminum myristate, calcium benzoate, potassium terephthalate, sodium terephthalate, sodium ethoxide, potassium phenoxide and the like can be used. . These metal compounds can be used alone or as a mixture. These metal compounds are used in an amount of 0.02 to 5.0 parts by weight, preferably 100 parts by weight of resin, and more preferably 0.1 to 100 parts by weight of PAT.
0.5 to 5 parts by weight.

In the present invention, PAT and AR are mixed together, and an acid anhydride and a metal compound or DGP and a metal compound are mixed in the above-mentioned ratios, respectively, and the mixture is put into an extruder, and the mixture is placed in the extruder. The mixture is heated and melted, and the mixture is kneaded to form a uniform composition. At this time, it is considered that PAT partially causes a transesterification reaction in this composition. Therefore, in order to obtain a uniform foam, it is preferable that the mixture is retained in the extruder for 90 seconds or more, and the peripheral speed of the screw is set to about 100 mm / second. Further, a transesterification catalyst may be added to promote the transesterification reaction. An acid or alkali compound can be used as the transesterification catalyst. After a uniform composition is thus obtained, a foaming agent is added to the composition.

Various foaming agents can be used. The foaming agent is dissolved and contained in the resin, but when the resin is melted and placed under a low pressure, the foaming agent volatilizes in the resin and acts to generate air bubbles.
Such blowing agents include inert gases, saturated aliphatic hydrocarbons,
Saturated alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers, ketones and the like. To give a concrete example,
Carbon dioxide gas, nitrogen, etc. can be used as the inert gas, ethane, propane, butane, pentane, hexane, etc. can be used as the saturated aliphatic hydrocarbon, and methylcyclopropane, cyclopentane can be used as the saturated alicyclic hydrocarbon. , Cyclohexane or the like, benzene or the like as an aromatic hydrocarbon, and methyl chloride, ethyl chloride, chlorodifluoromethane, 1,1-dichloro-2,2,2-trichloromethane as a halogenated hydrocarbon. Fluoroethane, 1-chloro-2, 2-difluoroethane, and the like can be used. As the ether, methyl ethyl ether, dimethyl ether, methyl tertiary butyl ether, and the like can be used. As the ketone, acetone, methyl ethyl ketone, and the like can be used. it can.

In order to include the above-mentioned blowing agent in a composition comprising PAT, AR, acid anhydride or DGP and a metal compound,
It is desirable to inject the blowing agent into the molten composition in an extruder. In this case, the ratio of the foaming agent to the composition is preferably such that the foaming agent accounts for 0.1 to 20% by weight in the composition.

When the method of the present invention is carried out, various auxiliaries can be further added, if necessary, in addition to the composition and the foaming agent. For example, a cell regulator such as talc powder can be added. Further, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a release agent, a dye, a pigment, a flame retardant, an antistatic agent, a filler, and the like can be added.

In order to extrude and foam, it is necessary to attach a base to the tip of the extruder. The base may be a circular orifice, even if the orifice provided there is linear. There may be. When a sheet-like foam is to be obtained, a die having an annular orifice is preferable.

In the method of the present invention, it is preferable that the foam extruded from the die has a density of 0.7 g / cc or less.

[0032]

According to the method of the present invention, PA is used as the resin.
A mixture of T and AR is used, and 100 parts by weight of the resin contains 0.02 to 5.0 parts by weight of each of the acid anhydride and the metal compound, or 0.02 to 5.0 parts by weight of DGP and the metal compound.
Since 0 parts by weight is added, regardless of whether the resin is crystalline, the viscosity of the resin when heated and melted increases, and the resin becomes a state suitable for foaming. Therefore, a resin foam can be easily produced by including a foaming agent therein.
In the present invention, 99-50 parts by weight of PAT and AR1
５０50 parts by weight to form a composition.When the composition is mixed with a foaming agent and extruded and foamed, the obtained foam has uniform and smaller air bubbles than conventional foams. It has a good quality, and when it is heated and molded, it foams more greatly to give a molded body with a smooth and beautiful surface, and the resulting molded body has better dimensional stability when heated. . Further, the foam and the molded article have good heat resistance and weather resistance. The present invention provides such advantages.

[0033]

Next, the advantages of the method of the present invention will be specifically described with reference to examples and comparative examples. In the following Examples and Comparative Examples, the glass transition temperature of the resin, the tensile strength and elongation of the foam, the cell diameter, the secondary moldability, the secondary foaming rate, the weather resistance and the heating dimensional change were measured. It was measured according to the following method. Also, simply below or%
Means, respectively, parts by weight or% by weight.

(1) Glass transition point. Differential scanning calorimeter (DSC 200 manufactured by Seiko Instruments Inc.)
0) according to the method specified in JIS K 7121. (2) Tensile strength and elongation. Universal testing machine (Orientec, Tensilon UTC
-10), and measured according to the method specified in JIS K6301. (3) Bubble diameter. Scanning electron microscope (JEOL, JSM-T300)
Take a picture at 50x magnification using ASTM 35
Measured according to 76-77. (4) Secondary formability. A 30 cm × 30 cm foam sheet was heated on a hot plate at 180 ° C. for 8 seconds, and then cooled to a diameter of 1 mm by a cooling mold at about 20 ° C.
It was molded into a cup having a depth of 0 cm and a depth of 10 cm. The evaluation was evaluated as ◎ when the thickness of the cup was uniform and glossy without unevenness on the surface, and as を when the thickness of the cup was uniform but uneven and glossy on the surface, and the corner of the cup was evaluated. If the thickness is slightly thinner than the other parts, the surface has irregularities and the appearance is poor, then mark △ .If the thickness of the cup corner is thinner than the other parts, and the surface has irregularities and the appearance is extremely poor, mark x. did. (5) Secondary expansion ratio. After leaving the foamed sheet obtained by extrusion foaming for 2 weeks, it is cut into a size of 30 cm × 30 cm, and is heated by being brought into contact with a hot plate at 180 ° C. for 30 seconds. The divided value was defined as the secondary expansion ratio. (6) Weather resistance. JIS A1 except that the test was performed using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.) without spray water.
415 was measured. The tensile strength and the tensile elongation retention showed the ratio of the value after 60 hours to the value at the beginning. (7) Heat dimensional change rate. The foamed sheet obtained by extrusion foaming was left for 2 weeks, cut into a size of 15 cm × 15 cm, heated in an oven at 60 ° C. for 24 hours, and measured for dimensions. The percentages are shown. -Indicates shrinkage.

[0035]

Example 1 As PAT, polyethylene terephthalate (trade name: TR8580, manufactured by Teijin Limited) (hereinafter referred to as PAT)
ET), and polyarylate (product name: U-Polymer P-1001A, manufactured by Unitika Ltd.) (hereinafter referred to as PAR) was used as AR. First, PET was placed in a dehumidifying dryer and dried at 160 ° C. for 4 hours while circulating air having a dew point of −30 ° C. PAR is also 140
Dry at 6 ° C. for 6 hours.

97 parts of PET and 3 parts of PAR are mixed, and 1 part of talc (an air conditioner), 0.33 part of pyromellitic anhydride and 0.05 part of sodium carbonate are added thereto.
This mixture was placed in an extruder having a diameter of 65 mm. The above mixture was melted by heating the barrel temperature of the extruder to 270 to 290 ° C., kneaded well in the extruder, and 0.9 parts of butane was injected as a foaming agent from the middle of the barrel. In this way, a foamable resin is made in the extruder, extruded from a circular die as a cylindrical sheet, foamed, slid on a cylindrical mandrel and taken off, and a part of the cylindrical sheet is cut open to form a flat sheet. This was wound up as a sheet. Thus, the thickness is 1.3 mm and the basis weight is 40
A foamed sheet having a density of 0 g / m ² and a density of 0.31 / cm ³ was obtained.

The obtained sheet has a glass transition temperature of 7
7.5 ° C., tensile strength of 7.3 MPa, tensile elongation of 146
%, Bubble diameter is 0.27, secondary formability is ◎, secondary foaming ratio is 2.93, weather resistance tensile strength retention is 68.5%, tensile elongation retention is 27.4%, heating dimension stability Rate is -0.5%
And it was excellent.

[0038]

Example 2 This example was performed in the same manner as in Example 1, except that the mixing ratio of PET and PAR was changed. The mixing ratio was 95 parts for PET and 5 parts for PAR.

The foamed sheet obtained by extrusion foaming has a glass transition point of 78.3 ° C. and a tensile strength of 7.8 MPa.
a, tensile elongation is 140%, cell diameter is 0.24 mm, secondary formability is ◎, secondary foaming rate is 2.81, weather resistance tensile strength retention is 74.4%, tensile elongation retention is 30 0.7% and a dimensional stability under heating of -0.5%, which were excellent.

[0040]

Example 3 This example was performed in the same manner as in Example 1, except that the mixing ratio of PET and PAR was changed. The mixing ratio was 90 parts of PET and 10 parts of PAR.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 79.9 ° C. and a tensile strength of 8.1 M.
Pa, tensile elongation is 129%, cell diameter is 0.21 mm, secondary moldability is ◎, secondary foaming ratio is 2.87, weather resistance tensile strength retention is 85.2%, and tensile elongation retention is 51. 0.6%,
The dimensional stability upon heating was -0.5%, which was excellent.

[0042]

Example 4 This example was performed in the same manner as in Example 1, except that the mixing ratio of PET and PAR was changed. The mixing ratio was 80 parts for PET and 20 parts for PAR.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 83.9 ° C. and a tensile strength of 9.0 M.
Pa, tensile elongation 93%, cell diameter 0.18 mm, secondary moldability 性, secondary foaming rate 2.70, weather resistance tensile strength retention 94.4%, tensile elongation retention 93 0.5% and a dimensional stability under heating of -0.3%, which were excellent.

[0044]

Embodiment 5 This embodiment was carried out in the same manner as in Embodiment 1, except that only the mixing ratio of PET and PAR was changed. The mixing ratio was 60 parts for PET and 40 parts for PAR.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 97.0 ° C. and a tensile strength of 12.0 ° C.
MPa, tensile elongation was 73%, cell diameter was 0.17 mm, secondary formability was good, and secondary foaming rate was 2.72, which was good.

[0046]

Example 6 This example was performed in the same manner as in Example 1, except that the mixing ratio of PET and PAR was changed. The mixing ratio was 50 parts for PET and 50 parts for PAR.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 107.1 ° C. and a tensile strength of 13.
3MPa, tensile elongation 50%, bubble diameter 0.17mm,
The secondary moldability was Δ and the secondary foaming ratio was 2.50, which was good as a whole.

[0048]

Example 7 The same operation as in Example 4 was performed except that the winding speed of the foam sheet was doubled. The resulting foamed sheet had a thickness of 0.65 mm, a basis weight of 200 g / m ² ,
The density was 0.31 g / cm ³ . The appearance of the obtained foamed sheet was good.

[0049]

Example 8 This example was carried out in exactly the same manner as in Example 1, except that 0.5 parts by weight of diglycidyl phthalate was used instead of pyromellitic anhydride. The obtained sheet has a glass transition temperature of 77.3 ° C., a tensile strength of 7.2 MPa, a tensile elongation of 150%, and a cell diameter of 0.30.
mm, secondary formability was excellent, secondary foaming ratio was 2.95, and dimensional stability under heating was -0.5%, which was excellent and good.

[0050]

Comparative Example 1 This comparative example was carried out in exactly the same manner as in Example 1 except that PAR was not used.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 76.3 ° C. and a tensile strength of 6.7 M.
Pa, tensile elongation is 147%, cell diameter is 0.30 mm, secondary moldability is ◎, secondary foaming rate is 2.12, weather resistance tensile strength retention is 59.7%, and tensile elongation retention is 1 0.8%, the dimensional stability under heating is -4.9%, and the secondary formability is good, but the cell diameter is large, the secondary foaming ratio is small, the weather resistance is poor, and the material shrinks greatly when heated. Was inferior to

[0052]

Comparative Example 2 This comparative example was carried out in the same manner as in Example 1, except that only the mixing ratio of PET and PAR was changed. The mixing ratio was 99.5 parts for PET and 0.5 parts for PAR.
It is out of the scope of the present invention in that PAR is small.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 76.6 ° C. and a tensile strength of 7.0 M.
Pa, tensile elongation is 147%, cell diameter is 0.30 mm, secondary formability is ◎, secondary expansion ratio is 2.34, secondary formability is good, but cell diameter is large, secondary expansion Rate is small,
In addition, it was inferior because it shrank greatly when heated.

[0054]

Comparative Example 3 This comparative example was carried out in the same manner as in Example 1, except that the mixing ratio of PET and PAR was changed. The mixing ratio was 40 parts for PET and 60 parts for PAR.
To be outside the scope of the present invention.

The foamed sheet obtained by extrusion foaming has a glass transition temperature of 122.1 ° C. and a tensile strength of 14.
4 MPa, tensile elongation 28%, bubble diameter 0.18 mm,
The secondary moldability was x, the secondary foaming rate was 2.40, and the cell was excellent in that the number of bubbles was small.

[0056]

Comparative Example 4 This comparative example was performed in the same manner as in Comparative Example 1 except that the winding speed of the foam sheet was doubled.

The foamed sheet obtained by extrusion foaming had an appearance such that the surface was rubbed, and the sheet was cut or the like, making molding difficult.

Continuation of the front page (51) Int.Cl. ⁶ identification code FI B29K 105: 04 (58) Investigated field (Int.Cl. ⁶ , DB name) C08J 9/00-9/42 B29C 47/00-47 / 96 C08K 3/00-13/08 C08L 67/00-67/08

Claims (1)

(57) [Claims] 1. A polyester resin foam obtained by incorporating a foaming agent into a crystalline thermoplastic polyester resin obtained by esterifying an aromatic dicarboxylic acid and an aliphatic or alicyclic diol, and extruding and foaming the foaming agent. In the method for producing a compound, an aromatic dicarboxylic acid and 2
1 to 50 parts by weight of a polyarylate resin obtained by reacting a polyphenol with the above-mentioned polyester resin 99 to 50
Parts by weight, and 0.02 to 5.0 parts by weight of an organic compound or diglycidyl phthalate containing two or more acid anhydride groups in one molecule, and 1st, 2nd or 2nd of the periodic table. 0.02 to 5.0 parts by weight of a metal belonging to Group 3 are added, and these are mixed well to form a uniform composition, which is then extruded by adding a foaming agent thereto. A method for producing a polyester resin foam.