JP2007083572A - Manufacturing method of modified polyphenylene ether type resin foam and circular die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a modified polyphenylene ether type resin foam enabling manufacture of a modified polyphenylene ether type resin foam of a high ratio of open cells and a high foaming rate. <P>SOLUTION: The method comprises feeding a modified polyphenylene ether type resin to an extruder to melt and knead with a foaming agent, extruding the resultant mixture from a circular die attached to the tip of the extruder and foaming in order to manufacture a modified polyphenylene ether type resin foam of a ratio of open cells of ≥70% and a foaming rate of at least 20-fold. A temperature-adjusting passage is formed at the tip part of the outer die of the circular die, and a liquid temperature-adjusting medium is caused to flow through the temperature-adjusting passage so as to adjust the temperature of the land part of the circular die. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a modified polyphenylene ether resin foam having a high open cell ratio and a high expansion ratio, and a circular mold used in this production method.

  Conventionally, a modified polyphenylene ether-based resin foam sheet has been used as a base material for automobile interior materials because of its excellent light weight, rigidity, and moldability. And, in order to improve the interior environment of the automobile, sound absorption performance is also required for automobile interior materials, and as shown in Patent Document 1, the applicant has only an open cell layer mainly composed of open cells. And the modified polyphenylene ether resin sheet is laminated and integrated on both sides of the modified polyphenylene ether resin foam sheet having an open cell ratio of 50% or more, and the modified polyphenylene ether resin is formed from the surface of the modified polyphenylene ether resin sheet. A foam sheet for automobile interior materials was proposed in which a hole reaching the resin foam sheet was formed.

  However, the modified polyphenylene ether-based resin foam sheet having a high open cell ratio hardly causes secondary foaming when being molded into an automobile interior material such as a ceiling material. Therefore, the thickness is reduced by stretching during the molding or pressing force in the thickness direction. Therefore, there is a problem that it is impossible to obtain an automobile interior material having a sufficient thickness having excellent sound absorption and mechanical strength. In order to solve such a problem, the thickness of the modified polyphenylene ether-based resin foam sheet having a high open cell ratio before molding is made sufficiently thick without increasing the weight of the foamed sheet, that is, the modification It was necessary to increase the expansion ratio of the polyphenylene ether resin foam sheet.

  On the other hand, in order to increase the open cell ratio of the modified polyphenylene ether-based resin foam sheet, it is conceivable to perform extrusion foaming in a state where the extrusion temperature is increased and the melt viscosity of the resin during extrusion foaming is lowered.

  However, just by raising the extrusion temperature and lowering the melt viscosity of the resin during extrusion foaming as described above, the foam film immediately after extrusion foaming from the extruder cannot withstand the pressure of the foaming gas and breaks. Another problem arises in that foaming occurs, the foaming gas in the foamed sheet escapes, and the foaming ratio of the foamed sheet decreases.

  Therefore, it is conceivable to increase the amount of the foaming agent added, but since the foaming agent has a plasticizing action of the resin, the increase in the foaming agent causes a decrease in the viscosity of the resin during extrusion foaming. As a result, there was a new problem that unevenness occurred on the surface of the obtained foamed sheet and the surface property was lowered.

  When trying to laminate and integrate a thermoplastic resin sheet on the surface of such a foam sheet with reduced surface properties, adhesion failure occurs between the foam sheet and the thermoplastic resin sheet, or molding failure occurs during thermoforming. The problem that occurred.

  On the other hand, if the extrusion foaming temperature is lowered in order to improve the surface property of the foam sheet, the foaming ratio of the foam sheet is lowered, or closed cells are easily formed on the surface of the foam sheet, and the foam sheet continues. There was a problem that the bubble ratio was lowered and the sound absorbing performance of the foam sheet was lowered.

JP 2005-88873 A

  The present invention provides a method for producing a modified polyphenylene ether-based resin foam that can produce a modified polyphenylene ether-based resin foam having a high open cell ratio and a high expansion ratio, and a gold that can be suitably used for this method. Provide the mold.

  The method for producing a modified polyphenylene ether-based resin foam of the present invention is a method in which a modified polyphenylene ether-based resin is supplied to an extruder, melted and kneaded together with a foaming agent, and extruded and foamed from a circular mold attached to the tip of the extruder. A production method for producing a modified polyphenylene ether resin foam having a cell ratio of 70% or more and an expansion ratio of 20 or more, wherein a temperature control flow path is formed at the tip of an outer mold of the circular mold. The temperature of the land portion of the circular mold is adjusted by circulating a liquid temperature control medium in the temperature control flow path.

  The modified polyphenylene ether resin is not particularly limited, and is a mixture of a polyphenylene ether and a polystyrene resin represented by the following chemical formula 1, a modified polyphenylene ether obtained by graft copolymerization of a styrene monomer with the polyphenylene ether, A block copolymer obtained by oxidative polymerization of a mixture of a modified polyphenylene ether and a polystyrene resin, a phenol monomer represented by the following chemical formula 2 and a styrene monomer in the presence of a catalyst such as an amine complex of copper (II) And a mixture of this block copolymer and polystyrene resin. The modified polyphenylene ether resin may be used alone or in combination.

（Ｒ¹ 、Ｒ² は炭素数が１〜４のアルキル基又はハロゲン原子を示し、ｎは重合度を示す。）

(R ¹ and R ² represent an alkyl group having 1 to 4 carbon atoms or a halogen atom, and n represents the degree of polymerization.)

  Examples of the polyphenylene ether represented by the above chemical formula 1 include poly (2,6-dimethylphenylene-1,4-ether), poly (2,6-diethylphenylene-1,4-ether), poly (2, 6-dichlorophenylene-1,4-ether), poly (2,6-dibromophenylene-1,4-ether), poly (2-methyl-6-ethylphenylene-1,4-ether), poly (2- Chloro-6-methylphenylene-1,4-ether), poly (2-methyl-6-isopropylphenylene-1,4-ether), poly (2,6-di-n-propylphenylene-1,4-ether) ), Poly (2-bromo-6-methylphenylene-1,4-ether), poly (2-chloro-6-bromophenylene-1,4-ether), poly (2-chloro-6-ether) Rufeniren 1,4 ether) and the like, which may be used in combination be used alone, also the degree of polymerization n is usually that of 10 to 5000 is used.

（Ｒ³ 、Ｒ⁴ は炭素数が１〜４のアルキル基又はハロゲン原子を示す。）

(R ³ and R ⁴ represent an alkyl group having 1 to 4 carbon atoms or a halogen atom.)

  Examples of the phenolic monomer represented by the above chemical formula 2 include 2,6-dimethylphenol, 2,6-diethylpheninol, 2,6-dichlorophenol, 2,6-dibromophenol, 2-methyl-6- Ethylphenol, 2-chloro-6-methylphenol, 2-methyl-6-isopropylphenol, 2,6-di-n-propylphenol, 2-bromo-6-methylphenol, 2-chloro-6-bromophenol, Examples thereof include 2-chloro-6-ethylphenol, and these may be used alone or in combination.

  Examples of the polystyrene resin mixed with the polyphenylene ether, the modified polyphenylene ether, or the block copolymer include polystyrene, a copolymer of styrene and a vinyl monomer copolymerizable therewith, and high impact polystyrene. And polystyrene is preferred. In addition, the polystyrene-based resin may be used alone or in combination.

  Examples of the vinyl monomer include methyl methacrylate, acrylonitrile, methacrylonitrile, and butyl acrylate. Moreover, as high impact polystyrene, rubber components such as styrene-butadiene copolymer and styrene-butadiene-styrene block copolymer are added to polystyrene or a copolymer of styrene and a vinyl monomer copolymerizable therewith. The thing formed by adding 1 to 20 weight% is mentioned.

  Examples of the styrene monomer that is graft copolymerized with polyphenylene ether or block copolymerized with a phenol monomer include styrene; α-methylstyrene, 2,4-dimethylstyrene, p-methylstyrene, ethylstyrene, p- Examples thereof include alkylated styrene such as t-butylstyrene; halogenated styrene such as monochlorostyrene and dichlorostyrene.

  The modified polyphenylene ether resin is preferably a modified polyphenylene ether resin in which the phenylene ether component is 15 to 60% by weight and the styrene component is 85 to 40% by weight, and the phenylene ether component is 20 to 60% by weight. A modified polyphenylene ether resin having a styrene component of 80 to 40% by weight is more preferable, and a modified polyphenylene ether resin having a phenylene ether component of 25 to 50% by weight and a styrene component of 75 to 50% by weight is particularly preferable.

  This is because if the amount of the phenylene ether component in the modified polyphenylene ether-based resin is small, the heat resistance of the foamed sheet may be lowered, while if it is large, a good-quality foamed sheet may not be obtained.

  Then, the modified polyphenylene ether resin is supplied to an extruder, melted and kneaded together with a foaming agent, and extruded and foamed from a circular mold A attached to the tip of the extruder. The foaming agent is not particularly limited as long as it is conventionally used, and examples thereof include ethane, propane, butane, pentane, dimethyl ether, etc., and these may be used alone or in combination. Also good.

  If the temperature of the modified polyphenylene ether resin when the modified polyphenylene ether resin is supplied to the circular mold A (the resin temperature at the time of mold supply) is low, foaming of the modified polyphenylene ether resin becomes insufficient. The open cell ratio of the modified polyphenylene ether resin foam may be hindered, and the open cell ratio of the modified polyphenylene ether resin foam may decrease. On the other hand, if it is high, the foam is modified immediately after being extruded and foamed from the circular mold. Since the bubbles in the polyphenylene ether-based resin are excessively broken and the expansion ratio of the modified polyphenylene ether-based resin foam is lowered, it is preferable to adjust so that the following formula 3 is satisfied.

(Glass transition temperature of modified polyphenylene ether resin + 60 ° C) ≤ Resin temperature when supplying mold
≦ (Glass transition temperature of modified polyphenylene ether resin + 80 ° C.) ·· Formula 3

  Here, as shown in FIG. 1, the circular mold A includes an outer mold 1 and an inner mold 2 disposed and fixed in the outer mold 1. Consists of a large-diameter outer mold body 1A and a small-diameter outer mold tip 1B that is detachably connected to the front end surface of the outer mold body, and the inner mold 2 is an inner mold. The main body 2A includes an inner mold tip 2B that is detachably connected to the front end surface of the inner mold main body 2A.

  A resin flow path 4 is formed between the opposing surfaces of the outer mold 1 and the inner mold 2, and the resin flow path 4 gradually expands forward (extrusion direction) from the resin inlet 41. A cylindrical first flow path 42 having a diameter, a cylindrical second flow path 43 communicating with the first flow path 42 and having a substantially constant diameter, and communicating with the second flow path 43 and gradually moving forward. A cylindrical third channel 44 having a reduced diameter, a cylindrical fourth channel 45 communicating with the third channel 44 and having a substantially constant diameter, and communicating with the fourth channel 45 and forward. It is composed of a cylindrical flow path that gradually expands toward the surface, that is, a land portion 46, and a modified polyphenylene ether resin is extruded and foamed from a tip opening (lip) 46a of the land portion. The inner mold 2 is fixed and integrated with the outer mold 1 via the spider 3 in the second flow path 43.

  A plurality of band heaters 5, 5,... Are wound around the outer peripheral surface of the outer mold body 1A. When heating by the band heater becomes excessive, air is blown from an air ring (not shown). To cool.

  Further, as shown in FIG. 2, the outer temperature independent from each other is provided in both side portions in front of the connecting portion between the fourth flow path 45 and the land portion 46 in the tip end portion 1B of the outer mold A of the circular mold A. The adjusting channels 6 and 6 are formed so as to bypass the substantially half-circumferential portion of the outer mold tip portion 1B in a U shape in the circumferential direction of the outer mold tip portion 1B and to surround the land portion 46 from the outside. .

  Specifically, the outer temperature control flow path 6 includes a pair of outer temperature control flow path sections 61 and 62 extending in a circumferential direction and extending in parallel with each other on a substantially semicircular portion of the outer mold tip 1B. The outer end connecting channel portion 63 that connects and communicates between the opposite end portions of the channel portions 61 and 62, and the other end portion of the outer temperature adjusting channel portion 61 is connected to the inlet 61a. The other end of the flow control channel 62 is used as an outlet 62a, and the inlet 61a and the outlet 62a are configured to be opposed to the front of the spider 3. The inlet 61a of the outer temperature control channel 61 and the outlet 62a of the outer temperature control channel 62 are connected via a connection channel (not shown) that opens to the surface of the outer mold tip 1B. The temperature control medium is connected to a temperature controller that adjusts the temperature control medium to a predetermined temperature.

  Further, as shown in FIGS. 1 and 2, the inner portion of the circular die A at the tip 2B of the inner die is located in front of the connecting portion between the fourth flow path 45 and the land portion 46. An inner temperature control flow path portion 71 that opens at the center of the front end surface of the mold tip 2B and extends in the axial direction of the inner mold 2 and a cylindrical shape that is formed so as to surround the inner temperature control flow path portion 71 It comprises a temperature control flow path portion 72, and a disk-shaped flow path portion 73 that connects the inner temperature control flow path portion 71 and the opposed rear end portions of the cylindrical temperature control flow path portion 72 over the entire circumference. An inner temperature control flow path 7 is formed.

  Then, the temperature control medium is supplied from the inlets 61a and 61a of the outer temperature control channels 61 and 61 of the outer temperature control channels 6 and 6 of the circular mold A configured as described above, and the outer temperature control flow. The temperature is adjusted from the outside by circulating the paths 6 and 6, and then the temperature control medium is discharged from the outlets 62a and 62a of the outer temperature control channels 62 and 62 of the outer temperature control channels 6 and 6. To do. The temperature adjusting medium is not particularly limited as long as the temperature of the land portion 46 of the circular mold A can be adjusted from the outside. For example, in addition to a liquid temperature adjusting medium such as oil and water, air And a gaseous temperature control medium such as an inert gas is preferable, but a liquid temperature control medium excellent in temperature control action is preferable.

  In this way, the modified polyphenylene ether-based resin flowing in the land 46 of the circular mold A can be removed from the outside by circulating the temperature control medium through the outer temperature control channels 6 and 6 of the circular mold A. The temperature can be adjusted uniformly to the desired temperature.

  Accordingly, the temperature of the modified polyphenylene ether resin can be accurately adjusted to the optimum temperature for extrusion foaming from the circular mold A, so that the modified polyphenylene ether resin can have a melt viscosity suitable for extrusion foaming. The so-called internal foaming in which the ether-based resin is foamed in the land portion 46 of the circular mold A can be prevented, and the resulting modified polyphenylene ether-based resin foam has excellent surface properties. .

  Since the modified polyphenylene ether resin is extruded and foamed from the lip 46a of the circular mold A after the temperature is adjusted so as to have a melt viscosity suitable for extrusion foaming as described above, the modified polyphenylene ether resin Immediately after the foam is greatly foamed, immediately before the modified polyphenylene ether-based resin cools and the bubble shape is fixed, the bubble shape is broken at a good timing to make it open, and the shape of the open cell is immediately fixed. The resulting modified polyphenylene ether resin foam has a high expansion ratio and a high open cell ratio.

  Further, in the circular mold A, an outer side formed so as to surround the land part 46 from the outside in the outer mold tip 1B, instead of cooling by blowing air from a conventional air ring or the like. Since the temperature of the land 46 is controlled from the outside by circulating the temperature control medium through the temperature control channels 6 and 6, the outer mold body 1A is not unexpectedly cooled. The modified polyphenylene ether resin is melted suitable for extrusion foaming in the land 46 of the circular mold A without unnecessarily cooling the first to fourth flow paths 42 to 45 of the circular mold A. The temperature of the modified polyphenylene ether resin can be adjusted, and the modified polyphenylene ether resin is made to generate as little residual strain as possible. Can perform extrusion foaming of ether-based resin, it is possible to obtain the excellent dimensional stability modified polyphenylene ether-based resin foam.

  Here, if the temperature of the temperature control medium circulated in the outer temperature control flow path 6 of the outer mold tip 1B of the outer mold 1 is low, the modified polyphenylene ether-based resin is insufficiently foamed and modified. The open cell ratio of the polyphenylene ether-based resin foam may be inhibited, and the open cell ratio of the modified polyphenylene ether-based resin foam may be reduced. On the other hand, if it is high, the modified polyphenylene ether-based resin foams inside the circular mold. So-called internal foaming occurs, or bubbles in the modified polyphenylene ether resin are excessively broken immediately after being extruded and foamed from the circular mold, so that the surface property of the modified polyphenylene ether resin foam is deteriorated. However, since the expansion ratio is lowered, the temperature of the temperature adjustment medium flowing into the inlet 61a of the outer temperature adjustment flow path 6 can be adjusted so as to satisfy Equation 1. Masui. The glass transition temperature of the modified polyphenylene ether resin refers to a temperature measured in accordance with JIS K7121: 1987 “Plastic transition temperature measurement method”.

(Glass transition temperature of modified polyphenylene ether resin + 20 ° C.) ≦ temperature of temperature control medium ≦
(Glass transition temperature of modified polyphenylene ether resin + 35 ° C)

  Further, as described above, the modified polyphenylene which circulates in the circular mold A by circulating the temperature control medium in the outer temperature control flow path 6 formed in the outer mold tip 1B of the circular mold A. The temperature of the ether-based resin can be accurately adjusted until the melt viscosity is suitable for extrusion foaming, but the temperature control medium is also circulated in the inner temperature control flow path 7 formed in the inner mold tip 2B. By adjusting the temperature of the land 46 also from the inside, the modified polyphenylene ether-based resin flowing through the resin flow path 4 in the circular mold A is adjusted more reliably and accurately to a melt viscosity suitable for extrusion foaming. be able to. In addition, since the temperature control medium distribute | circulated in the inner side temperature control flow path 7 is the same as the temperature control medium distribute | circulated in the outer side temperature control flow path 6, the description is abbreviate | omitted.

  Specifically, a temperature control medium is supplied to the inner temperature control flow channel portion 71 of the inner temperature control flow channel 7 through the inlet 71a, and the inner temperature control flow channel portion 71 passes through the disk-shaped flow channel portion 73. The temperature control medium is supplied to and distributed through the cylindrical temperature control flow path 72 to adjust the temperature of the land 46 from the inside, and the temperature of the modified polyphenylene ether resin flowing through the land 46 of the circular mold A is adjusted from the inside. To do.

  In this way, the temperature adjustment medium is circulated in a cylindrical shape in the cylindrical temperature adjustment flow path portion 72 of the inner temperature adjustment flow path 7, and the temperature of the land portion 46 is uniformly adjusted from the inside to the circumferential direction. Therefore, the temperature of the cylindrical modified polyphenylene ether resin circulating in the land portion 46 of the circular mold A can be uniformly adjusted from the inner side in the circumferential direction.

  Here, if the temperature of the temperature control medium circulated in the inner temperature control flow path 7 of the inner die front end portion 1B is low, the foaming of the modified polyphenylene ether resin becomes insufficient and the modified polyphenylene ether resin foams. The open cell ratio of the modified polyphenylene ether resin foam may be reduced due to obstruction of the open body of the body, whereas if it is high, bubbles in the modified polyphenylene ether resin immediately after being extruded and foamed from the circular mold Is excessively broken, and the expansion ratio of the modified polyphenylene ether resin foam decreases, so that the temperature control flowing into the inlet 71a of the inner temperature control channel 71 of the inner temperature control channel 7 It is preferable to adjust so that the temperature of the medium satisfies Equation 2.

(Glass transition temperature of the modified polyphenylene ether resin-30 ° C.) ≦ temperature of the temperature control medium ≦
(Glass transition temperature of modified polyphenylene ether resin -10 ° C)

  As described above, the outer mold main body 1A and the outer mold main body 1A and the inner temperature control flow path 6 of the outer mold tip portion 1B and the inner temperature control flow path 7 of the inner mold tip portion 2B are circulated. With almost no cooling of the inner mold body 2A, the temperature of the land portion 46 is adjusted from the inside and outside directions, and the temperature of the modified polyphenylene ether resin in the molten state flowing through the land portion 46 is uniformly adjusted from the inside and outside directions. The polyphenylene ether-based resin can be accurately adjusted so as to have a melting temperature suitable for extrusion foaming.

  As described above, the modified polyphenylene ether-based resin whose temperature is adjusted so as to have a melt viscosity suitable for extrusion foaming in the land portion 46 of the circular mold A is extruded and foamed from the lip 46a of the circular mold A into a cylindrical shape. Thus, a cylindrical modified polyphenylene ether resin foam is obtained.

  Subsequently, after gradually expanding the diameter of the cylindrical modified polyphenylene ether resin foam, the cylindrical modified polyphenylene ether resin foam is continuously supplied to the mandrel and cooled, and then the cylindrical modified polyphenylene ether resin foam is extruded in the direction of extrusion. The modified polyphenylene ether-based resin foam sheet having a high foaming ratio of 20 times or more and an open cell ratio of 70% or more can be obtained.

  The open cell ratio of the modified polyphenylene ether-based resin foam sheet refers to that measured in accordance with ASTM D2856-87. Specifically, a plurality of planar square sheet-like test pieces each having a side of 25 mm are cut out from the modified polyphenylene ether-based resin foam sheet over the entire length in the thickness direction of the foam sheet. The laminated body is formed by superposing the whole thickness in the thickness direction so as to be about 25 mm.

Next, after accurately measuring the apparent volume of the laminate using a caliper, the volume is measured by the 1-1 / 2-1 atmospheric pressure method using an air-comparing hydrometer, and the open cell ratio is calculated by the following formula: Is calculated. In addition, the volume of the laminated body by the 1-1 / 2-1 atmospheric pressure method is measured using the air comparison type hydrometer which is marketed with the brand name "air comparison type hydrometer 1000 type | mold" from Tokyo Science, for example. be able to.
Open cell ratio (%) = 100 × (apparent volume−volume of laminate by air comparison hydrometer) /
Apparent volume

  The expansion ratio of the modified polyphenylene ether resin foam sheet is determined by measuring the apparent density of the modified polyphenylene ether resin foam according to JIS K7222, and determining the density of the modified polyphenylene ether resin by the modified polyphenylene ether resin foam. It is calculated by dividing by the apparent density.

  Here, the circular mold A has a spider 3 in which the inner and outer molds 2 and 1 are connected and integrated in the second flow path 43, and a modified polyphenylene ether resin that circulates through the second flow path 43. In spite of this, the flow is disturbed by the spider 3, and even if the modified polyphenylene ether-based resin in which the flow is disturbed is foamed, a good foam may not be obtained.

  On the other hand, the outer temperature control flow path 6 for adjusting the temperature of the land portion 46 of the circular mold A from the outside does not have a temperature control flow path between the inlet 61a and the outlet 62a. Between the inflow port 61a and the outflow port 62a, the temperature adjustment from the outside of the land portion 46 becomes insufficient.

  That is, among the modified polyphenylene ether resins that circulate in the land portion 46 of the circular mold A, the temperature adjustment of the modified polyphenylene ether resin that circulates in the land portion 46 facing the front of the spider 3 may be insufficient. There is.

  That is, among the modified polyphenylene ether resins that circulate through the resin flow path 4 of the circular mold A, the modified polyphenylene ether obtained by foaming the modified polyphenylene ether resin that circulates through the resin flow path 4 portion located in front of the spider 3. The ether-based resin foam part is deteriorated in quality as compared with other parts due to the presence of the spider 3 and insufficient temperature control.

  Therefore, in the circular mold A, the inlet 61a and the outlet 62a of the outer temperature control flow path 6 are provided at positions facing the front of the spider 3, so that the temperature of the modified polyphenylene ether resin affected by the spider is increased. All the problems of under-regulation are absorbed, and the two effects of spider and under-temperature regulation are prevented from reaching the modified polyphenylene ether resin not affected by the spider.

  Then, when the cylindrical modified polyphenylene ether resin foam is cut between the inner and outer peripheral surfaces and cut open, the modified polyphenylene ether type extruded and foamed from the lip 46a facing the front of the spider 3 in the circular mold A A modified polyphenylene ether resin foam sheet obtained by cutting a cylindrical modified polyphenylene ether resin foam from the resin foam portion to obtain a defective portion that is affected by spider 3 and insufficient temperature control, resulting in a deterioration in quality. The defective portions located at both end portions can be easily cut and removed, and a high-quality modified polyphenylene ether-based resin foam sheet can be easily obtained.

  The modified polyphenylene ether-based resin foam sheet thus obtained has a high open cell ratio and a high foaming ratio and sufficient thickness. Even if the thickness is reduced by the above, the molded product still has sufficient thickness and mechanical strength.

  In the circular mold A, the case where the U-shaped outer temperature control channels 6 and 6 are formed in both side portions of the outer mold tip 1B has been described. However, the land portion 46 is provided in the outer mold tip 1B. The land portion 46 may be configured to be temperature-controlled from the outside by forming an outer temperature control channel in a spiral shape so as to surround and circulating the above-described temperature control medium in the outer temperature control channel. Good.

  The method for producing the modified polyphenylene ether resin of the present invention is to supply the modified polyphenylene ether resin to an extruder, melt and knead it together with a foaming agent, and extrude and foam from a circular mold attached to the tip of the extruder. Is a manufacturing method for producing a modified polyphenylene ether-based resin foam having an expansion ratio of 20% or more, wherein a temperature control flow path is formed at the tip of the outer mold of the circular mold, Since the temperature of the land of the circular mold is controlled by circulating a temperature control medium in the temperature control flow path, the modified polyphenylene ether resin immediately before being extruded and foamed from the circular mold is used for extrusion foaming. A modified polyphenylene ether resin foam that can be adjusted to a suitable melt viscosity, has a high expansion ratio, and a high open cell ratio can be easily obtained. It is possible to elephants.

  In particular, a temperature control channel is formed at the outer mold tip of the circular mold, and a temperature control medium is circulated in the temperature control channel, so the tip of the outer mold in the outer mold of the circular mold The land portion of the circular mold can be accurately adjusted to the desired temperature from the outside and the modified polyphenylene ether-based resin can be further adjusted to a melt viscosity suitable for extrusion foaming, with almost no cooling of the other parts. Furthermore, a modified polyphenylene ether-based resin foam having a high expansion ratio and a high open cell ratio can be produced.

  The circular mold of the present invention is a circular mold used for extrusion foaming, and comprises an outer mold and an inner mold disposed and fixed in the outer mold via a spider. A resin flow path is formed between the opposing surfaces of the mold, and temperature control flow in which both sides of the front end of the outer mold bypass the substantially half circumference of the front end of the outer mold in a U-shape in the circumferential direction. Since the flow path is provided and the inlet and outlet of these temperature control flow paths are provided at positions facing the front of the spider, the outer mold part other than the outer mold tip part The temperature of the land part can be intensively adjusted from the outside, and the melted resin just before extrusion foaming can be adjusted to a melt viscosity suitable for extrusion foaming. Can be done.

Example 1
A tandem type extruder having a second extruder connected to the tip of the first extruder is prepared, and the circular mold A shown in FIGS. 1 and 2 is provided at the tip of the second extruder of the tandem type extruder. Attached.

  First, 65 parts by weight of a mixture of polyphenylene ether and polystyrene resin (trade name “NORYL PKN4752” manufactured by GE Plastics, phenylene ether component: 70 wt%, styrene component: 30 wt%), and polystyrene (manufactured by Toyo Styrene Co., Ltd.) Modified polyphenylene ether resin obtained by mixing 35 parts by weight of a trade name “HRM-26” (phenylene ether component: 45.5% by weight, styrene resin component: 54.5% by weight, glass transition temperature: 146 ° C. ) And 0.7 parts by weight of talc are supplied to the first extruder and melt kneaded, and 4.0 parts by weight of a foaming agent comprising 35% by weight of isobutane and 65% by weight of normal butane is injected into the first extruder. After melt kneading at 250 ° C., the molten resin is continuously supplied to the second extruder connected to the tip of the first extruder. And after adjusting so that the resin temperature is 213 ° C. and was fed to the circular die A attached to the tip of the second extruder.

  On the other hand, the outer mold body 1A of the circular mold A is heated by the band heaters 5, 5,... And the heating of the outer mold body 1A by the band heaters 5, 5,. The outer mold body 1A of the circular mold A was maintained at 190 ° C. by blowing air from the air ring that was not cooled.

  Further, the oil heated to 175 ° C. is continuously supplied into the outer temperature control channels 6 and 6 formed in the outer mold tip 1B of the circular mold A through the inlet 61a, and the outer temperature control flow. The oil is continuously discharged from the outlets 62a and 62a of the outer temperature control channels 6 and 6, and the inner temperature formed in the inner mold tip 2B of the circular mold A is circulated in the channels 6 and 6. Oil maintained at 125 ° C. is supplied into the inner temperature control channel portion 71 of the temperature control channel 7 through the inlet 71a, and is cylindrical from the inner temperature control channel portion 71 via the disk-shaped channel portion 73. The temperature of the land portion 46 was continuously adjusted from the inside to the outside by supplying and circulating oil to the temperature control flow path 72 and discharging the oil out of the cylindrical temperature control flow path 72.

  After the temperature of the molten modified polyphenylene ether resin supplied to the circular mold A is adjusted in the first to third flow paths 42 to 44 and the second flow path 45 of the circular mold A, this modified In the land portion 46, the polyphenylene ether resin is circulated in the outer temperature control channels 6 and 6 of the outer mold tip 1B and in the inner temperature control channel 7 of the inner mold tip 2B. Then, the temperature was adjusted so that the melt viscosity was suitable for extrusion foaming by cooling from the inside and outside, and the modified polyphenylene ether resin was extruded from the lip 46a of the circular mold A into a cylindrical shape.

  Subsequently, after gradually expanding the diameter of the cylindrical foam and continuously supplying and cooling the mandrel, the cylindrical foam is continuously cut and expanded between the inner and outer surfaces in the extrusion direction. Thus, a modified polyphenylene ether resin foam sheet was obtained. In the circular mold A, the cylindrical foam was cut and developed at the cylindrical foam portion extruded from the lip 46a facing the front of the spider 3 in the circular mold A. When the surface of the obtained modified polyphenylene ether-based resin foam sheet was visually observed, no fracture (unevenness) occurred on the foam sheet surface.

(Example 2)
A modified polyphenylene ether-based resin foam sheet was obtained in the same manner as in Example 1 except that the amount of the foaming agent was 4.4 parts by weight instead of 4 parts by weight. When the surface of the obtained modified polyphenylene ether-based resin foam sheet was visually observed, no fracture (unevenness) occurred on the foam sheet surface.

(Comparative Example 1)
A band heater is wound around the outer peripheral surface of the outer mold tip 1B without circulating oil through the inner and outer temperature control channels 7 and 6 of the inner and outer mold tips 2B and 1B. While heating 1B, when heating of the outer mold tip 1B by this band heater becomes excessive, air was blown from the air ring (not shown) to the outer peripheral surface of the outer mold tip 1B, and maintained at 190 ° C. A modified polyphenylene ether-based resin foam sheet was obtained in the same manner as in Example 1 except that.

  When the surface of the obtained modified polyphenylene ether resin foamed sheet was visually observed, fractures were generated on the foamed sheet surface.

(Comparative Example 2)
A band heater is wound around the outer peripheral surface of the outer mold tip 1B without circulating oil through the inner and outer temperature control channels 7 and 6 of the inner and outer mold tips 2B and 1B. While heating 1B, when heating of the outer mold tip 1B by the band heater was excessive, air was blown from the air ring (not shown) to the outer peripheral surface of the outer mold tip 1B and maintained at 155 ° C. A modified polyphenylene ether resin foam sheet was obtained in the same manner as in Example 1 except that.

  When the surface of the obtained modified polyphenylene ether-based resin foam sheet was visually observed, no fracture occurred on the surface of the foamed sheet, but the closed cells having a thickness of about 1 mm were formed on the surface of the modified polyphenylene ether-based resin foam sheet. A layer was formed.

  The resulting modified polyphenylene ether-based resin foamed sheet was measured for open cell ratio, foaming ratio, thickness, basis weight, and apparent density, and the results are shown in Table 1.

It is the longitudinal cross-sectional view which showed the circular metal mold | die. It is the perspective view which showed the inner and outer land part of the circular metal mold | die.

Explanation of symbols

1 Outer mold
1A outer mold body
1B Outer mold tip 2 Inner mold
2A Inner mold body
2B Inner mold tip 3 Spider 4 Resin flow path
46 Land
46a Lip 5 Band heater 6 Outer temperature control flow path
61a inlet
62a Outlet 7 Inner temperature control flow path

Claims (5)

The modified polyphenylene ether resin is supplied to an extruder, melted and kneaded together with a foaming agent, extruded and foamed from a circular mold attached to the tip of the extruder, and has an open cell ratio of 70% or more and an expansion ratio of 20 times or more. A manufacturing method for producing a modified polyphenylene ether resin foam, wherein a temperature control flow path is formed at the tip of an outer mold of the circular mold, and a temperature control medium is circulated in the temperature control flow path. A method for producing a modified polyphenylene ether-based resin foam, characterized in that the temperature of a land portion of the circular mold is controlled. The method for producing a modified polyphenylene ether-based resin foam according to claim 1, wherein the temperature control medium circulated in the temperature control flow path is a liquid. The modified polyphenylene ether resin according to claim 1 or 2, wherein the temperature of the temperature control medium flowing into the inlet of the temperature control flow path at the tip of the outer mold is adjusted so as to satisfy Formula 1. A method for producing a foam.
(Glass transition temperature of modified polyphenylene ether resin + 20 ° C.) ≦ temperature of temperature control medium ≦
(Glass transition temperature of modified polyphenylene ether resin + 35 ° C.) Formula 1 A temperature control channel is formed at the tip of the inner mold of the circular mold, and the temperature of the land of the circular mold is controlled by circulating a temperature control medium in the temperature control channel, and the tip of the inner mold The modified polyphenylene ether system according to any one of claims 1 to 3, wherein the temperature of the temperature control medium flowing into the inlet of the temperature control flow path of the section is adjusted so as to satisfy Formula 2. Manufacturing method of resin foam.
(Glass transition temperature of the modified polyphenylene ether resin-30 ° C.) ≦ temperature of the temperature control medium ≦
(Glass transition temperature of modified polyphenylene ether-based resin −10 ° C.) Formula 2 A circular mold used for extrusion foaming, comprising an outer mold and an inner mold disposed and fixed in the outer mold via a spider, and a resin between the opposing surfaces of the inner and outer molds A flow path is formed, and a temperature control flow path is provided in each side portion of the outer mold front end portion of the outer mold so that a substantially half-circumferential portion of the outer mold front end portion is detoured in a U shape in the circumferential direction. And a circular mold characterized in that an inlet and an outlet of these temperature control channels are provided at positions facing the front of the spider.

Images