JPH11240975A - Production of molded thermoplastic foam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a molded thermoplastic foam capable of ensuring the retention of a shape on foaming and enabling the acquisition of a deformed thermoplastic foam having a high foaming ratio. SOLUTION: This method for producing a molded thermoplastic foam comprises molding a foaming resin composition comprising 0.5-30 pts.wt. of a thermal decomposition type foaming agent and 100 pts.wt. of a resin composition comprising 0.5-30 wt.% of a fibril-like liquid crystal resin and 70-99.5 wt.% of a thermoplastic resin by an extrusion molding method, a press molding method, a vacuum or air pressure molding method or a blow molding method at a temperature which is higher than the melting point of the thermoplastic resin and below the decomposition-initiating temperature of the thermal decomposition type foaming agent, and subsequently foaming the obtained foaming molded product at a higher temperature than the decomposition temperature of the thermal decomposition type foaming agent.

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 thermoplastic shaped foam used for, for example, interior materials for automobiles and building materials, and more particularly to a method for producing a resin composition containing a thermoplastic resin and a liquid crystal resin. The present invention relates to a method for producing a foamed thermoplastic molded foam which is formed and foamed and has excellent shape retention during foaming.

[0002]

2. Description of the Related Art Polyolefin foams are excellent in heat insulation, light weight and flexibility, and therefore are required to be compatible with both cushioning and light weight for automobile interior materials, such as sun visors, door pads and ceilings. Shaped foams made of polyolefin foams are widely used as materials. For example, Japanese Utility Model Publication No. Hei 4-21807 discloses an automotive interior material made of polyethylene foam and a method for producing the same.

[0003] Foams used for interior materials for automobiles are rarely used as flat members, and are formed into a desired shape by secondary processing of the flat foam.

[0004] However, since the secondary press requires a dedicated press die and batch molding, the production efficiency is poor and the stability of quality is not so high.

[0005] Therefore, attempts have been made to obtain a deformed foam by foaming a deformable foamable shaped body. However, it is difficult to obtain a deformed foam having a desired shape by a method of foaming a deformable foamable shaped article having low shape retention during foaming. It is considered that this is because the elongation stress of the resin at the time of foaming is insufficient, and the foamable shaped body foams particularly in a direction in which foaming is easy, that is, in a direction in which the foaming is not performed.

[0006] In recent years, heat resistance has been emphasized in automotive interior materials. Therefore, in order to enhance heat resistance, attempts have been made to foam engineering plastics. In particular, various studies have been made on foam molded articles using a liquid crystal polymer. For example, Japanese Unexamined Patent Publication
Japanese Patent Application Laid-Open No. 179042 discloses a method for producing a foam molded article using a liquid crystal polymer.

However, when only the liquid crystal polymer is foamed, the expansion ratio is as low as 2 times or less, and it has been difficult to use it as an interior material for automobiles that requires lightness as well as heat resistance.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to use a deformable expandable shaped body having an increased elongation stress at the time of foaming, thereby ensuring shape retention at the time of foaming and achieving a high expansion ratio. It is an object of the present invention to provide a method for producing a thermoplastic shaped foam capable of obtaining a deformed thermoplastic shaped foam.

[0009]

According to a first aspect of the present invention, there is provided a resin composition obtained by mixing 0.5 to 30% by weight of a fibril-like liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin. Thermal decomposition type foaming agent 0.5 to 3 parts per 100 parts by weight
0 parts by weight of the foamable resin composition is extruded from a deformed mold at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the thermal decomposition type foaming agent, and then the thermal decomposition type foaming agent is decomposed. A method for producing a thermoplastic shaped foam, characterized in that a shaped foam is obtained by heating the foam to a temperature or higher.

[0010] The invention according to claim 2 is based on 100 parts by weight of a resin composition obtained by mixing 0.5 to 30% by weight of a liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin.
A foamable resin composition obtained by mixing 0.5 to 30 parts by weight of a pyrolytic foaming agent is extruded from a deformed mold at a temperature not lower than the decomposition temperature of the pyrolytic foaming agent and not lower than the liquid crystal transition point of the liquid crystal resin. Thereafter, the method is a method for producing a thermoplastic shaped foam, characterized by obtaining a shaped foam by reheating to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent.

According to a third aspect of the present invention, in the method for producing a thermoplastic shaped foam according to the second aspect,
Upon extruding the foamable resin composition from a deformed mold,
It is characterized by being extruded at a temperature not lower than the decomposition temperature of the thermal decomposition type foaming agent, exceeding the transition point of the liquid crystal resin, and not higher than 300 ° C.

According to a fourth aspect of the present invention, a fibril-like liquid crystal resin is contained in an amount of 0.5 to 30% by weight and a thermoplastic resin is used in an amount of 70 to 9%.
With respect to 100 parts by weight of a resin composition containing 9.5% by weight,
A sheet-like foamable resin composition obtained by mixing 0.5 to 30 parts by weight of a pyrolytic foaming agent is press-molded at a temperature not lower than the melting temperature of the thermoplastic resin and less than the decomposition temperature of the pyrolytic foaming agent. This is a method for producing a thermoplastic shaped foam, which comprises shaping, followed by heating to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent to obtain a shaped foam.

According to a fifth aspect of the present invention, there is provided a fibril-like liquid crystal resin of 0.5 to 30% by weight and a thermoplastic resin of 70 to 9%.
With respect to 100 parts by weight of a resin composition containing 9.5% by weight,
A sheet-shaped foamable resin composition obtained by mixing 0.5 to 30 parts by weight of a thermal decomposition type foaming agent is vacuum-formed or molded at a temperature not lower than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the thermal decomposition type foaming agent. This is a method for producing a thermoplastic shaped foam, characterized in that a shaped foam is obtained by heating to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent after shaping by pressure forming.

According to a sixth aspect of the present invention, there is provided a fibril-like liquid crystal resin of 0.5 to 30% by weight and a thermoplastic resin of 70 to 9%.
With respect to 100 parts by weight of a resin composition containing 9.5% by weight,
A foamable resin composition obtained by mixing 0.5 to 30 parts by weight of a thermal decomposition type foaming agent is extruded into a parison at a temperature not lower than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the thermal decomposition type foaming agent. A method for producing a thermoplastic shaped foam, characterized in that a shaped foam is obtained by heating a deformed shaped body obtained by molding to a temperature not lower than a decomposition temperature of a pyrolytic foaming agent.

Hereinafter, the present invention will be described in detail. (Liquid crystal resin) The liquid crystal resin that can be used in the present invention is not particularly limited as long as it has a liquid crystal transition point higher than the melting point of the thermoplastic resin used. Preferred are thermoplastic liquid crystal polyesters such as polyesters and thermoplastic polyesteramides. Specifically, commercially available wholly aromatic polyester liquid crystal resins such as Vectra (manufactured by Polyplastics, Sumika Super (manufactured by Sumitomo Chemical Co., Ltd.), Zyder (manufactured by Nippon Petrochemical Co., Ltd.) An aromatic polyester resin is exemplified.

The mixing ratio of the liquid crystal resin to the thermoplastic resin is 0.5 to 0.5% with respect to 100% by weight of the total amount of the thermoplastic resin and the liquid crystal resin in order that the elongation stress of the foamable resin composition is sufficient. To 30% by weight, preferably 1 to 25% by weight, more preferably 3 to 2% by weight.
0% by weight. When the mixing ratio of the liquid crystal resin is less than 0.5% by weight, the shape retention during foaming cannot be sufficiently ensured. When the mixing ratio exceeds 30% by weight, the elongation stress becomes too high and the three-dimensional uniformity is increased. Foamability will be reduced.

When the elongation stress required at the time of foaming is represented by the elongational viscosity of the foamable resin composition, it is 8,000 poise to 3,000 poise.
It is preferably in the range of 0 poise (190 ° C.), more preferably 10,000 poise to 27000 poise (1
90 ° C.), and more preferably in the range of 12000 to 25000 poise (190 ° C.). Elongational viscosity is 8000
In the case of lower than poise, the portion other than the imprinted portion foams intensively, and it may be difficult to obtain a deformed foam having the same shape as the expandable shaped object stage, and if it is higher than 30,000 poise, , The elongation stress becomes too high, the foaming property decreases,
In some cases, the expansion ratio does not increase and a uniform deformed foam cannot be obtained. The elongational viscosity is JIS K
It is a value measured according to 7117.

The liquid crystal resin needs to be fibrils in a thermoplastic resin matrix prior to foaming. Since the liquid crystal resin is in the form of fibrils, a high elongation stress during foaming is ensured, and foaming can be performed three-dimensionally and evenly.

Although the fibril-shaped liquid crystal resin is mixed with the thermoplastic resin in the first, third to fifth aspects of the present invention, the liquid crystal resin is fibrillated from the beginning in the second aspect. It is not always necessary to extrude the foamable resin composition from a deformed mold at a temperature equal to or higher than the decomposition temperature of the thermal decomposition type foaming agent and equal to or higher than the transition point of the liquid crystal resin.

Here, the fibril state refers to a state in which the aspect ratio (dispersion length / dispersion diameter) of the liquid crystal resin dispersed in the thermoplastic resin matrix exceeds 1. This aspect ratio is preferably set to 10 or more. The fibril diameter is 0.1 to 100 μm.
m is preferable, and 1 to 10 μm is more preferable.

When the above liquid crystal resin is fibrillated, an external stress such as a shear stress or an elongation stress is applied to the composition comprising the thermoplastic resin and the liquid crystal resin at a temperature not lower than the liquid crystal transition point of the liquid crystal resin. The liquid crystal resin can be fibrillated.

For example, when the thermoplastic resin and the liquid crystal resin are melted and kneaded, a shear stress is applied in an extruder or a mold, whereby the liquid crystal resin can be easily fibrillated. The apparent shear rate applied to the mixed resin composition necessary for forming the liquid crystal resin into fibrils in the matrix resin is 1 × 10 ² to 1 × 10 ⁵ sec ⁻¹ , preferably 3 × 10 ² to 1 ×. Desirably, 10 ⁴ sec ^-1 .
The liquid crystal resin in the mixed resin composition extruded at a shear rate in this range easily undergoes fibrillation, and can usually be a fibril-like liquid crystal resin having a fibril diameter of 10 μm or less and a fibril length of 0.1 mm or more. .

(Thermoplastic Resin) The thermoplastic resin used in the present invention is not particularly limited as long as it is a foamable thermoplastic resin, and examples thereof include low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. ,
Olefinic resins such as homopolypropylene, block polypropylene and random polypropylene; ethylene-
Vinyl acetate copolymer; polyvinyl chloride; polystyrene and the like. Among them, olefin resins are preferably used because the flexibility required for interior materials for automobiles can be realized.

In either case where the melt index (MI) of the thermoplastic resin is too large or too small, the foaming stability is reduced. Therefore,
Preferably, the MI of the thermoplastic resin is 0.1 to 20 g / 1.
0 minute, preferably 0.2 to 15 g / 1
More preferably, the range is 0 minutes. In addition, MI in this specification is a value measured according to JIS K7210.

The above-mentioned thermoplastic resin may be cross-linked as required. By using the cross-linked thermoplastic resin, it is possible to foam at a higher magnification and to obtain a foamed molded article. The weight can be reduced, and the thermal stability can be improved.

The crosslinking method is not particularly limited, and examples thereof include an electron beam crosslinking method in which an ionizing radiation such as an electron beam is irradiated, a chemical crosslinking method using an organic peroxide, and a silane crosslinking method using a silane-modified resin. Can be mentioned.
If the degree of cross-linking of the thermoplastic resin is too high, the expansion ratio decreases and the flexibility decreases.If the degree of cross-linking is too low, the thermal stability decreases and the cells break during foaming to obtain uniform cells. Can not. Therefore, the gel fraction serving as an index of the degree of crosslinking is preferably in the range of 10 to 30% by weight, and more preferably 10 to 20% by weight.

The gel fraction in the present specification refers to the percentage by weight of the residue weight after immersing the expandable thermoplastic resin in xylene at 120 ° C. for 24 hours based on the weight of the crosslinked resin component before immersion in xylene. Shall be referred to.

In the present invention, if necessary, the mixed composition containing the liquid crystal resin and the thermoplastic resin may be added to the mixed composition containing the liquid crystal resin and the thermoplastic resin before molding or in order to increase the compatibility thereof. A compatibilizer may be added during molding. Examples of the compatibilizer include, when the thermoplastic resin is an olefin resin, a copolymer of an olefin component and a styrene component or an aromatic polyester component; an olefin resin having a maleic acid component or an acrylic acid component;
An olefin resin copolymer having a glycidyl methacrylate component can be used. Further, the amount of the compatibilizer to be added may be appropriately selected according to the composition and the mixing ratio of the mixed system.

The pyrolytic foaming agent used in the present invention is not particularly limited as long as it has a decomposition temperature higher than the melting temperature of the thermoplastic resin used. Examples thereof include sodium bicarbonate, ammonium carbonate, and bicarbonate. Inorganic pyrolytic foaming agents such as ammonium, azide compounds and sodium borohydride; azodicarbonamide, azobisisobutyronitrile, N, N'-dinitrosopentamethylenetetramine, p, p'-dinitrosopentamethylene Organic thermal decomposition-type foaming agents such as tetramine, p, p'-oxybisbenzenesulfonylhydrazide, barium azodicarboxylate, and trihydrazinotriazine can be used, and the decomposition temperature and decomposition rate can be easily adjusted. Use of azodicarbonamide is particularly high due to its high amount of generation and excellent hygiene Preferred.

The amount of the foaming agent to be added is 0.5 to 100 parts by weight of the total of the liquid crystal resin and the thermoplastic resin.
It is necessary to use 30 parts by weight, preferably 1 to 20 parts by weight. When the addition ratio of the foaming agent is less than 0.5 part by weight, the foaming becomes insufficient, and it becomes difficult to obtain a deformed foam. When it exceeds 30 parts by weight, the foaming pressure at the time of foaming increases. Exceeding the elongation stress, the cells break, and a deformed foam cannot be obtained.

(The manufacturing method according to the first aspect of the present invention)
In the invention according to claim 1, the fibril-like liquid crystal resin, the thermoplastic resin, and the pyrolytic foaming agent are mixed and foamed by heat to obtain a deformable foamable shaped body by a general method. The thermoplastic resin, the liquid crystal resin, and the pyrolytic foaming agent may be blended, melt-kneaded, and extruded from a mold having an irregular shape, and specific steps are not particularly limited. Above all, the degree of kneading can be increased,
In addition, it is preferable to use a twin-screw kneading extruder because foam stability can be improved.

The molding temperature at the time of extrusion from a mold having an irregular shape must be equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent. When the temperature is higher than the decomposition temperature of the thermal decomposition type foaming agent, primary foaming is caused when extruding from a mold having an irregular shape. Conversely, when extruding below the melting temperature of the thermoplastic resin, the back pressure becomes too high, and It cannot be extruded from the shaped mold.

The irregularly shaped mold is appropriately constituted according to the shape of the desired irregularly shaped foam. For example, when the purpose is to obtain a deformed foam having a tub-like shape, a tub-shaped foaming shaped body may be obtained by using a tub-shaped deformed mold. When a corrugated shaped foam is obtained, a corrugated foamed shaped body may be obtained by using a corrugated deformed mold.

In these cases, the dimensions of the resin discharge portion of the deformed mold are obtained by reducing the expansion ratio of the desired deformed foam to one third root in each of the two directions of the vertical and horizontal directions. Needs to be That is, when obtaining a tub-shaped foam having a foaming ratio of 20 times, a tub-shaped deformed mold having a resin discharge portion of one third root of 20 in each of the vertical and horizontal directions is used. I just need.

In the case of performing the above-mentioned electron beam crosslinking or silane crosslinking, a step of extruding the expandable thermoplastic resin from a mold having an irregular shape, and a treatment according to a crosslinking method may be performed after the step.

The foamed extrudate is extruded from the deformed mold, heated to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent, and then cooled to a temperature lower than the softening point of the thermoplastic resin and solidified to form the deformed foam. Obtainable. In this case, the heating and cooling methods are not particularly limited.

For example, the heating method is performed by putting the foamable shaped body in a heating furnace in which the outside is kept at a constant temperature, or by blowing hot air on the foamed shaped body. What is necessary is just to cool to below the melting temperature of a thermoplastic resin using the method of blowing cold air, the method of immersing a shaped foam in cold water, etc.

(Production method of the invention according to claims 2 and 3)
In the production method according to the second aspect of the invention, a resin composition obtained by mixing a liquid crystal resin and a thermoplastic resin at the above specific ratio is used, as in the first aspect. In this case, the liquid crystal resin does not have to be in the form of fibrils.

A foamable resin composition obtained by mixing the above liquid crystal resin and the thermoplastic resin in a proportion of 0.5 to 30 parts by weight of the pyrolytic foaming agent with respect to 100 parts by weight of the resin composition. Is heated above the decomposition temperature of the thermal decomposition type foaming agent and above the transition point of the liquid crystal resin to cause primary foaming and extrude from the deformed mold. As a result, an elongation stress is applied to the liquid crystal resin, and the liquid crystal resin is fibrillated.

The expansion ratio at the time of the primary expansion is 1.5 to 10
It is preferably about twice, more preferably 2 to 8 times. If the expansion ratio at the time of the primary foaming is lower than 1.5 times, the elongation stress at the time of the primary foaming is insufficient, so that the liquid crystal resin may not be sufficiently fibrillated. It may be too large, causing foam breakage in the next step of foaming, making it impossible to obtain a foam having a desired expansion ratio.

The expansion ratio at the above-mentioned primary expansion stage,
In order to control the final expansion ratio at the stage when the secondary foaming performed later is completed, in the invention according to claim 2, the addition amount of the pyrolytic foaming agent is determined by the liquid crystal resin and the thermoplastic resin. Preferably, the amount is 1 to 30 parts by weight based on 100 parts by weight. When the use ratio of the thermal decomposition type foaming agent is less than 1 part by weight, the expansion ratio may not be sufficiently increased, and when it exceeds 30 parts by weight, it becomes difficult to control the expansion ratio in the primary expansion stage.

In the production method according to the second aspect of the present invention, after the mixed resin composition is extruded from the odd-shaped mold as described above, the mixed resin composition is heated again to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent. Complete secondary foaming. In this case, the foaming is completed by the decomposition of the pyrolytic foaming agent remaining at the primary foaming end stage. Also in this case, since the liquid crystal resin is in the form of fibrils and dispersed in the thermoplastic resin matrix, the elongation stress at the time of foaming is high, and the foam is evenly three-dimensionally foamed. As a result, foaming is completed while maintaining the shape extruded from the deformed mold, and a thermoplastic shaped foam according to the deformed mold can be obtained.

In the production method according to the third aspect of the present invention, when the foamable resin composition is extruded from a deformed mold, the temperature of the foamable resin composition is set to the decomposition temperature of the pyrolytic foaming agent. Extrusion is performed at a temperature exceeding the transition point of the liquid crystal resin and 300 ° C. or less. Other points are the same as those of the second aspect. in this way,
The reason for setting the temperature at the time of extruding the foamable resin composition to the above specific range is as follows.

That is, as described above, the liquid crystal resin includes a wholly aromatic liquid crystal resin and a semi-aromatic liquid crystal resin. Among them, a wholly aromatic liquid crystal resin is excellent in heat resistance.

Therefore, in applications where good heat resistance is required, a wholly aromatic liquid crystal resin is used. However, the wholly aromatic liquid crystal resin has a liquid crystal transition point, that is, a temperature at which a solid liquid crystal polymer becomes a liquid crystal state at 285.
High around ℃. Therefore, it is necessary to increase the molding temperature accordingly. When a wholly aromatic liquid crystal resin is blended with a general thermoplastic resin and used, the molding temperature range becomes narrow.

On the other hand, the liquid crystal resin easily fibrillates when subjected to shearing force or elongational flow at a temperature higher than the liquid crystal transition point during molding. However, once the fibrillated material is left in a stress-free state at a temperature equal to or higher than the liquid crystal transition point, the liquid crystal resin returns to a spherical shape again in the thermoplastic resin of the matrix.

Therefore, in the invention according to claim 3, when extruding the foamable resin composition, the temperature of the foamable resin composition is set to a temperature exceeding the transition point of the liquid crystal resin and 300 ° C. or less. That is, by controlling the foamable resin composition within this temperature range, the liquid crystal resin is fibrillated, and is cooled immediately below the liquid crystal transition point after the fibrillation. Therefore, the liquid crystal resin is fibrillated and maintained in a state where its aspect ratio is high. When the aspect ratio is maintained in a high state, the specific surface area of the liquid crystal fibrils increases, and the effect of reinforcing the thermoplastic resin can be enhanced.

When the temperature of the foamable resin composition at the time of extrusion is lower than the liquid crystal transition point of the liquid crystal resin,
The liquid crystal resin does not melt, making molding difficult,
If the temperature exceeds 00 ° C., after extruding from the extruder, it is relaxed to a fibril state before cooling, and the aspect ratio decreases.

(Production method of the invention according to claim 4) In the method for producing a thermoplastic shaped foam according to the invention described in claim 4, the fibril-like epoxy resin is produced in the same manner as in the invention described in claim 1. Resin 0.5 to 30% by weight and thermoplastic resin 70
Resin composition 100 mixed at a ratio of ９９99.5% by weight
A foamable resin composition in which a pyrolysis type foaming agent is mixed in a ratio of 0.5 to 20 parts by weight with respect to parts by weight is used. However, in the invention according to claim 4, a sheet-shaped foamable resin composition is used as the foamable resin composition, and press molding is performed at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent. To shape.

In order to obtain the sheet-like foamable resin composition, a thermoplastic resin, a liquid crystal resin and a pyrolytic foaming agent may be blended, melt-kneaded and formed into a sheet by a general method. In this case, it is preferable to use a twin-screw kneading extruder since the kneading degree can be increased and the foaming stability can be increased.

Further, as for the method of forming the mixed resin composition extruded from the extruder into a sheet, the resin composition extruded from a T-die attached to the tip of the extruder is formed into a pair of opposed resin sheets having a predetermined clearance. What is necessary is just to pass between cooling rolls.

The size of the clearance between the pair of cooling rolls is desirably set to be 0.2 to 0.5 mm smaller than the target thickness. When the clearance is smaller than the above range, the surface smoothness of the sheet may be reduced. When the clearance is larger than the above range, the sheet may be thinner than a target thickness. In the case where the above-mentioned electron beam crosslinking or silane crosslinking is performed, a process according to a crosslinking method may be performed after the step of forming the expandable thermoplastic resin into a sheet and after the step.

In the invention according to claim 4, the sheet-like foamable resin composition obtained as described above is treated at a temperature not lower than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent. Injection molding and shaping. In this case, a method can be used in which the desired deformed foam is shaped by a press die having a scale factor corresponding to the expansion ratio of the deformed foam. In other words, when obtaining a deformed foam having an expansion ratio of 20 times, shaping is performed with a press die that is scaled down to one third of the 20th root of the deformed foam in each of the three directions of vertical × horizontal × height. do it.

Next, the obtained foamable shaped body is heated to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent to cause foaming, and then cooled to a temperature lower than the softening temperature of the thermoplastic resin. A solid foam can be obtained by solidification. The method of foaming, heating and cooling is not particularly limited, and the same heating method and cooling method as in the first aspect of the invention can be used.

(Production method of thermoplastic shaped foam according to the invention of claim 5) In the invention of claim 5, in the same manner as in the invention of claim 4, a sheet-like foamable resin composition Get things. Thereafter, the sheet-shaped foamable resin composition is
It is heated to a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent, and shaped by vacuum forming or pressure forming to obtain a foamable shaped body.

The method for heating the sheet-like foamable resin composition is not particularly limited, and examples thereof include a method in which the sheet-like foamable resin composition is put into a far-infrared oven and heated. The air pressure used when performing vacuum forming and compressed air forming is 1 kg / cm ^{2 to} 10 kg /
cm ² , more preferably 3 cm ²
８8 kg / cm ² . Air pressure is 1kg / cm
When it is lower than ^2, it may be difficult to faithfully shape the molding die in detail, and when it exceeds 10 kg / cm ² , the sheet-like foamable resin composition may be broken.

The temperature of the air at the time of performing the vacuum forming and the pressure forming is preferably room temperature, whereby it is possible to perform the steps from the shaping to the cooling at the same time. As a shaping mold used for shaping, a shaping mold having a scale ratio corresponding to the expansion ratio of a desired deformed foam may be used. In other words, when it is desired to obtain a deformed foam having an expansion ratio of 20 times, a press mold reduced in scale to one third of the 20th root of the deformed foam in each of the three directions of length × width × height. It may be used.

Next, the obtained foamable shaped body is heated to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent to foam.
Thereafter, the thermoplastic resin is cooled to a temperature equal to or lower than the softening temperature of the thermoplastic resin and solidified to obtain a deformed foam. In this case, the heating and cooling methods are not particularly limited, and can be performed in the same manner as the first aspect of the present invention.

(Method for Producing a Thermoplastic Shaped Article According to the Invention According to Claim 6) In the method for producing a thermoplastic shaped foam according to the invention according to claim 6, the method according to claim 1 Using the same foamable resin composition as in the production method, extruded in a parison shape at a melting temperature of the thermoplastic resin or higher and lower than the decomposition temperature of the pyrolytic foaming agent, blow-molded, shaped into an irregular shape, and foamed. Obtain the excipient.

In this case, in order to extrude the resin composition in a parison shape, for example, the resin composition may be melt-kneaded by a single screw extruder and then extruded from a parison-shaped mold. The temperature at the time of extrusion is a temperature higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent.

Next, blow molding is performed using a mold corresponding to the deformed foam having the desired shape. What is necessary is just to use the shaping die used for blow molding which has a scale ratio according to the expansion ratio of the target deformed foam. That is,
When it is desired to obtain a deformed foam having an expansion ratio of 20 times, a blow molding die reduced to one third root of 20 of the deformed foam in each of the three directions of vertical × horizontal × height. It may be used.

It is desirable that the blow mold is cooled to a temperature lower than the melting temperature of the thermoplastic resin by, for example, water cooling. Also, the air pressure during blow molding is preferably in the range of 1 to 10 kg / cm ^2, more preferably from 3~8kg / cm ^2. If the air pressure is lower than 1 kg / cm ² , faithful shaping over the details of the shaping mold may be difficult, and
If it exceeds 0 kg / cm ² , the parison-like foamable resin composition may break during molding.

The foamable shaped body obtained by blow molding is foamed by heating it to a temperature not lower than the decomposition temperature of the pyrolytic foaming agent, and then cooled to a temperature lower than the softening point of the thermoplastic resin and solidified. By doing so, a deformed foam can be obtained. The heating and cooling methods in this case can be performed in the same manner as in the first aspect of the present invention.

(Function) In the method for producing a thermoplastic shaped foam according to the first aspect of the present invention, the resin composition containing the fibril-like liquid crystal resin and the thermoplastic resin in the above-described specific ratio is thermally decomposed and foamed. The foaming resin composition obtained by mixing the agents in the above-mentioned specific ratio is extruded from a deformed mold at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent, so that the foaming property can be improved. A shaped body is obtained, and by heating the foamable shaped body to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent, a shaped foam can be obtained.

In this case, since the liquid crystal resin is dispersed in the form of fibrils in the thermoplastic resin, the elongation stress at the time of foaming increases, and the elongation stress increases. It hardly occurs and foaming stability is increased.
Therefore, the foam is three-dimensionally and uniformly foamed without being affected by the residual stress of the previously shaped portion. in addition,
By extruding the above-mentioned resin composition from a deformed mold, a deformable foamable shaped body can be continuously obtained.

In the second aspect of the invention, when the foamable resin composition to which the liquid crystal resin is added is primarily foamed, the liquid crystal resin is fibrillated and dispersed in the thermoplastic resin matrix. Therefore, the elongation stress at the time of foaming of the foamable shaped body having the irregular shape is increased, and as in the case of the first aspect of the invention, the cell membrane is hardly broken at the time of foaming, and the foaming stability is enhanced. Therefore, similarly to the first aspect of the present invention, foaming is performed three-dimensionally and uniformly without being affected by the residual stress of the previously formed portion. In addition, by extruding from a mold having a modified cross section, a deformable foamable shaped body can be obtained continuously.

According to a third aspect of the present invention, in the manufacturing method according to the second aspect, the temperature of the foamable resin composition at the time of extrusion exceeds the liquid crystal transition point of the liquid crystal resin and is 300 ° C. or less. Because it is the temperature of, it can be stably extruded from a deformed mold, and the liquid crystal resin that has been made into a fibril with a high aspect ratio is cooled immediately after extrusion while maintaining a high aspect ratio, The shaped foam is effectively reinforced by the high aspect ratio liquid crystal fibrils.

Also in the invention according to claim 4, the foamable resin composition in which the fibril-like liquid crystal resin, the thermoplastic resin and the pyrolytic foaming agent are mixed at the above-mentioned specific ratio, is heated to a temperature higher than the melting temperature of the thermoplastic resin. In addition, since the shape is formed at a temperature lower than the decomposition temperature of the thermally decomposable foaming agent, a foamable shaped body in which the fibril-like liquid crystal resin is dispersed can be obtained in the same manner as in the first aspect of the present invention. According to the fourth aspect of the present invention, in order to obtain the foamable shaped body, the foamable shaped body is obtained by press-molding the sheet-shaped foamable resin composition.

Since the fibril-like liquid crystal resin is dispersed in the expandable shaped article, the foamable shaped article is heated to a temperature not lower than the decomposition temperature of the thermal decomposition type foaming agent. Due to the increase in the elongation stress at the time of foaming, it is difficult for the cell membrane to be broken, and the foaming stability is enhanced,
Foaming can be performed three-dimensionally evenly without the foaming being hindered by the residual stress of the previously shaped portion. Therefore, a foam having a desired shape can be reliably obtained.

According to the fifth aspect of the present invention, similarly to the fourth aspect of the present invention, the sheet-like foamable resin composition is heated at a temperature not lower than the melting temperature of the thermoplastic resin and at the decomposition starting temperature of the pyrolytic foaming agent. However, in the invention according to the fifth aspect, the shape is formed by vacuum molding or air pressure molding. However, similarly to the invention according to the fourth aspect, it is possible to easily obtain an expandable shaped body. it can. Moreover, since the foamable shaped body is foamed by heating it to a temperature equal to or higher than the decomposition temperature of the pyrolytic foaming agent to obtain a shaped foam, the elongation during foaming is the same as in the invention of claim 4. The stress increases, the cell membrane is hardly broken at the time of foaming, the foaming stability is enhanced, and the foaming is uniformly performed three-dimensionally without being affected by the residual stress of the previously shaped portion. it can.

Also in the invention according to claim 6, since the foamable resin composition according to claim 1 is shaped to obtain a foamable shaped body, a fibril-like liquid crystal resin is formed in the foamable shaped body. Is dispersed in the thermoplastic resin matrix, so that when the foamable shaped body is foamed by heating it to a temperature higher than the decomposition temperature of the pyrolytic foaming agent, the elongation stress during foaming increases. Therefore, due to the increase in the elongation stress, the cell membrane is less likely to be broken during foaming, foaming stability is increased, and foaming is not hindered by the residual stress of the previously shaped portion, and three-dimensionally. It will be evenly foamed.

In the foaming according to the sixth aspect, in order to obtain the foamable shaped body, the foamable resin composition is extruded into a parison shape and then blow-molded to obtain the foamable shaped body. It is possible to easily obtain a molded article suitable for being obtained by blow molding such as a cylinder.

[0073]

The present invention will now be described in detail with reference to non-limiting examples.

Example 1 Polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: EA9A, MI = 0.3 g / 10 min, density 0.9 g / cm ³ , melting temperature 165 ° C.) and liquid crystal resin (manufactured by Unitika) , Trade name: Rodrun LC-5000,
And a liquid crystal transition temperature of 280 ° C.) at a ratio shown in Table 1 below, and a twin-screw kneading extruder (trade name: PC, manufactured by Ikegai Kiko Co., Ltd.)
M-30), melt-kneaded, extruded from a strand die having a diameter of 3 mm, cooled with water, and pelletized with a pelletizer to obtain a liquid crystal resin / thermoplastic resin pellet. In this case, the barrel temperature and the mold temperature are both 290 ° C.
Set to. The composite pellet was frozen with liquid nitrogen, fractured, and the fracture surface was observed with a scanning electron microscope. As a result, the liquid crystal resin in the composite pellet was fibrillated.

Next, the above-mentioned composite pellets and silane-crosslinkable polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon XP)
M800HM, MI = 10 g / 10 min, melting temperature 167
℃) and silane crosslinking catalyst master batch (Mitsubishi Chemical Corporation,
Product name: PZ-10S, 100 parts by weight of polypropylene with 1 part by weight of dibutyltin laurate added)
And a thermal decomposition type foaming agent (azodicarbonamide, manufactured by Otsuka Chemical Co., Ltd., trade name: Uniform AZ, SO-20, decomposition temperature 201 ° C.) at a ratio shown in Table 2 below, and a twin screw kneading extruder ( Melted and kneaded with Ikegai Kiko Co., Ltd., trade name: PCM-30), and the resin discharge portion 1a shown in FIG. 1 was extruded from the corrugated deformed mold 1, and the extruded shaped body was water-cooled with water at 20 ° C. Thereafter, the resultant was cut into a length of 100 mm to obtain a foamable shaped body. In this case, the barrel temperature and the mold temperature were both set at 180 ° C.

The expansion ratio of the expandable shaped body obtained as described above was measured. That is, the density of the shaped foam is measured,
The result was divided by the density of the foamable resin composition, and the reciprocal thereof was defined as the expansion ratio. The results are shown in Table 3 below.

Thereafter, the foamable shaped body was heated at 100 ° C.
In hot water for 2 hours to crosslink. The crosslinked foamable excipient is placed on a sheet made of tetrafluoroethylene, and 2
Put into a heating oven controlled at 30 ° C.
The mixture was allowed to stand for a minute and heated and foamed. After the heating and foaming, the foam was taken out of the heating oven and allowed to cool naturally to solidify the deformed foam.

The curvature of the curved surface of the deformed foam obtained as described above was measured at the position indicated by A in FIG. The curved surface portion was regarded as a part of a circular arc, and the radius of the circular arc was measured to obtain the radius of curvature of the curved surface portion. From the radius of curvature thus obtained, the deviation of the radius of curvature from the uniform foam was calculated by the following equation (1).

[0079]

(Equation 1)

In the equation (1), X is the ratio (%) of deviation of the radius of curvature of the curved surface from the uniform foaming, R is the radius of curvature of the curved surface, T is the average foaming ratio of the whole, R0 indicates the radius of curvature of the curved surface portion before foaming.

[0081] Note that if uniform foaming, since a ^{R / T 2/3, R / T} 2/3 becomes a uniformity index of the foam, therefore, in the above formula (1), R / T ^{2 The} ratio of deviation from uniform foaming was determined based on the ratio of R ^{/ 3} to R0.

Further, the resulting deformed foams in the vertical, horizontal,
And the actual size of the height was measured using a scale. From the dimensions thus obtained, the ratio Y of the deviation from the uniform foaming of each of the expansion ratios of the vertical, horizontal and height was calculated by the calculation method shown in the following equation (2).

[0083]

(Equation 2)

In the formula (2), Y represents a ratio (%) of deviation from vertical, horizontal or uniform foaming of height, expressed by L
Represents the actual size of the length, width or height, L0 represents the dimension before foaming of the length, width or height, and T represents the average average expansion ratio. Table 4 below shows the results obtained by the equation (2).

Example 2 The proportions of the resins used are shown in Tables 1 and 2.
A molded foam was obtained and evaluated in the same manner as in Example 1 except for the following changes.

(Comparative Example 1) Table 1
A shaped foam was obtained and evaluated in the same manner as in Example 1 except that the shape was changed as in Example 2.

(Comparative Example 2) Table 1
A shaped foam was obtained and evaluated in the same manner as in Example 1 except that the shape was changed as in Example 2.

Example 3 A foamable resin composition having the composition shown in Tables 1 and 2 below was melt-kneaded by a twin-screw kneading extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.). Extruded from the mold shown in FIG. 1, water-cooled with water at 20 ° C., solidified,
It was cut to a length of 100 mm to obtain a primary foamed foamable shaped body. In this case, the barrel temperature and the mold temperature were both set to 290 ° C.

The expansion ratio of the expandable shaped body obtained as described above was measured. That is, the expansion ratio was obtained by measuring the density of the foamable shaped body that was primarily foamed, dividing the result by the density of the foamable resin composition, and calculating the reciprocal thereof. The results are shown in Table 5 below.

The foamable shaped body was immersed in hot water at 100 ° C. for 2 hours to crosslink. The crosslinked foamable excipient is placed on a tetrafluoroethylene sheet, placed in a heating oven temperature-controlled at 230 ° C., and left for 10 minutes,
Heat and foam.

After the heating and foaming, the foam was taken out of the heating oven, allowed to cool, and the shaped foam was solidified. A part of the shaped foam was broken, and the broken surface was observed with a scanning electron microscope. As a result, it was confirmed that 80% or more of the liquid crystal resin was fibrillated and dispersed.

Further, the expansion ratio of the shaped foam was measured. Regarding the measurement of the expansion ratio, the density of the shaped foam was measured, divided by the density of the expandable resin composition, and the reciprocal thereof was obtained. Table 5 shows the results.

Thereafter, the curvature and actual size of the shaped foam were measured in the same manner as in Example 1. Further, in the same manner as in Example 1, the amount of deviation from the uniform foaming of the radius of curvature and the deviation of the expansion ratio in each of the vertical, horizontal, and height directions from the uniform foaming were calculated. The results are shown in Tables 5 and 6 below.

Example 4 A shaped foam was obtained in the same manner as in Example 3 except that the mixing ratio of the pyrolytic foaming agent was changed as shown in Table 2, and the same as in Example 3. Was evaluated.

Comparative Example 3 As shown in Tables 1 and 2 below, a shaped foam was prepared in the same manner as in Example 3 except that only polypropylene was used without using a liquid crystal resin. Obtained and evaluated.

Comparative Example 4 As shown in Tables 1 and 2 below, liquid crystal resin was added to 350 parts by weight of polypropylene.
A shaped foam was obtained and evaluated in the same manner as in Example 3, except that 00 parts by weight was used.

Comparative Example 5 As shown in Table 1 below, a shaped foam was produced in the same manner as in Example 3 except that the proportion of polypropylene was 600 parts by weight and the liquid crystal resin was 200 parts by weight. Was obtained and evaluated.

[0098]

[Table 1]

[0099]

[Table 2]

[0100]

[Table 3]

[0101]

[Table 4]

[0102]

[Table 5]

[0103]

[Table 6]

As is clear from Tables 3 and 4, in Examples 1 and 2 as compared with Comparative Example 1 in which no liquid crystal resin was used.
Probably because the polypropylene and the liquid crystal resin are blended according to the invention of claim 1 and the liquid crystal resin is fibrillated and dispersed, the deviation from the uniform foaming of the curvature radius is extremely small, and the obtained shaped foam is It can be seen that the deviation from uniform foaming is extremely small in any of the vertical, horizontal, and height directions, and thus a shaped foam that is three-dimensionally and uniformly foamed can be obtained.

Also, in Comparative Example 2, the deviation from uniform foaming was large as in Comparative Example 1, probably because the compounding ratio of the liquid crystal resin was too high. It was big.

As is clear from Tables 5 and 6,
In Comparative Examples 3 and 4 in which the liquid crystal resin was not used, Comparative Example 4 in which the compounding ratio of the liquid crystal resin was too large, and Comparative Example 5 in which the compounding ratio of the liquid crystal resin was too small, in Examples 3 and 4, the radius of curvature was changed from uniform foaming. The deviation was very small, and the deviation from uniform foaming in the vertical, horizontal, and height directions in the obtained shaped foam was also very small.

Example 5 Polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: EA9A, MI = 0.3 g / 10 min, density 0.9 g / cm ³ , liquid crystal resin (produced by Unitika, trade name: Rodrun LC) -5000, liquid crystal transition temperature 280
° C) at the ratio shown in Table 7 below, melt-kneaded with a twin-screw kneading extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.), extruded from a 3 mm diameter strand die, and water-cooled.
By pelletizing with a pelletizer, liquid crystal resin /
A polypropylene composite pellet was obtained. When the cross section of this composite pellet was observed with a scanning electron microscope, the liquid crystal resin was fibrillated and dispersed. In addition, at the time of the above-mentioned melt kneading and extrusion, both the barrel temperature and the mold temperature were set to 290 ° C.

Next, the above-mentioned composite pellets, silane-crosslinkable polypropylene (trade name: Linklon XP, manufactured by Mitsubishi Chemical Corporation)
M800HM, melting temperature 167 ° C., MI = 10 g / 10
), A silane crosslinking catalyst master batch (manufactured by Mitsubishi Chemical Corporation, trade name: PZ-10S), and azodicarbonamide as a pyrolysis type foaming agent (manufactured by Otsuka Chemical Co., trade name: Uniform AZ SO-20, decomposition) At a temperature shown in Table 8 below, and melt-kneaded with a twin screw extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.), and extruded from a sheet die having a lip clearance of 2 mm and a width of 200 mm. By sizing with a pair of upper and lower water-cooled rolls, a foamable sheet having a thickness of 2 mm and a width of 180 mm was obtained. At this time, the barrel temperature and the mold temperature were both set at 180 ° C.

Thereafter, the foamable sheet obtained as described above was cut into a length of 200 mm, and a press die composed of an upper die and a lower die shown in FIGS. It was pressed at a pressing pressure of 1 kg / cm ² , and cut so that the lengths of the vertical and horizontal sides were 180 mm and 130 mm, respectively, to obtain a foamable shaped body.

[0110] The obtained foamable shaped body is allowed to cool to room temperature,
Thereafter, it was immersed in hot water at 100 ° C. for 2 hours to perform crosslinking.
The crosslinked foamable shaped body was placed on a sheet made of tetrafluoroethylene, placed in a heating oven temperature-controlled at 230 ° C., left for 10 minutes, and heated and foamed. After the heating and foaming, the foam was taken out of the heating oven, allowed to cool, and the shaped foam was solidified.

As described above, the shaped foam 2 shown in FIG. 4 was obtained. At the positions A to C of the shaped foam, the curvature radius and the deviation of the curvature radius from the uniform foaming were evaluated in the same manner as in Example 1. In addition, the actual size of the length, width and height of the obtained shaped foam was measured using calipers, and the same calculation method as in Example 1 was used to calculate the expansion ratio in each direction of the length, width and height. The deviation from uniform foaming was calculated. The results are shown in Table 9 below.

Example 6 Except that the composition of the resin used was changed as shown in Tables 7 and 8 below,
A shaped foam was obtained and evaluated in the same manner as in Example 5.

Example 7 A shaped foam was obtained and evaluated in the same manner as in Example 5, except that the mixing ratio of the pyrolytic foaming agent was changed as shown in Table 8 below. .

(Comparative Examples 6 and 7) Except that the resin composition used was changed as shown in Tables 7 and 8 below,
A shaped foam was obtained and evaluated in the same manner as in Example 5.

(Comparative Examples 8 and 9) Except that the mixing ratio of the pyrolytic foaming agent was changed as shown in Table 8 below,
A shaped foam was obtained and evaluated in the same manner as in Example 5.

Example 8 Polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: EA9A, MI = 0.3 g / 10 min, density: 0.9 g / cm ³ ) and liquid crystal resin (produced by Unitika, trade name: rod run) LC-5000, liquid crystal transition temperature 280
° C) at the ratio shown in Table 7 below, melt-kneaded with a twin-screw kneading extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.), extruded from a 3 mm diameter strand die, and water-cooled.
By pelletizing with a pelletizer, liquid crystal resin /
A polypropylene composite pellet was obtained. The composite pellet was broken, and the fracture surface was observed with a scanning electron microscope. As a result, it was confirmed that the liquid crystal resin was fibrillated and dispersed. In addition, at the time of the above-mentioned melt kneading and extrusion, the barrel temperature and the mold temperature were both set to 290 ° C.

Next, the above-mentioned composite pellet and silane-crosslinkable polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: Linklon X)
PM800HM), a silane crosslinking catalyst masterbatch (manufactured by Mitsubishi Chemical Corporation, trade name: PZ-10S), and azodicarbonamide (manufactured by Otsuka Chemical Co., Ltd.) as a pyrolytic foaming agent.
Product name: Unihall AZ SO-20, decomposition temperature 201
° C) at a ratio shown in Table 8 below, and melt-kneaded with a twin-screw kneading extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.), extruded from a sheet die having a lip clearance of 2 mm and a width of 200 mm, and By sizing with a pair of water-cooled rolls, a foamable sheet having a thickness of 2 mm and a width of 180 mm was obtained. At this time, the barrel temperature and the mold temperature were both set at 180 ° C.

Thereafter, the foamable sheet obtained as described above was cut into a height of 200 mm, placed in a heating oven controlled at a temperature of 180 ° C., and heated for 5 minutes.
The foamable sheet was in a molten state. Subsequently, the foamable sheet in the molten state was weighed by 5 kg using a shaping die shown in FIG.
Compressed air was formed using compressed air having an air pressure of / cm ² , and then the molded body was cut into a length and a width of 140 mm to obtain a foamable shaped body.

The foamed shaped body was allowed to cool to room temperature, and then immersed in hot water at 100 ° C. for 2 hours to crosslink. The crosslinked foamable excipient was placed on a tetrafluoroethylene sheet, placed in a heating oven controlled at 230 ° C., left for 10 minutes, and foamed by heating. After heating and foaming
The molded foam was taken out of the heating oven, allowed to cool, and the shaped foam was solidified.

The deviation of the radius of curvature and the radius of curvature of the shaped foam from the uniform foaming and the deviation of the foaming ratio of the shaped foam from the uniform foaming in each of the vertical, horizontal and height directions are shown in FIG. In the positions corresponding to the parts shown in FIGS.
The evaluation was performed in the same manner as described above. The results are shown in Table 10 below.

Comparative Example 10 A shaped foam was obtained and evaluated in the same manner as in Example 8, except that the resin composition used was changed as shown in Tables 7 and 8 below. .

Example 9 Polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: EA9A, MI = 0.3 g / 10 min, density 0.9 g / cm ³ , liquid crystal resin (produced by Unitika, trade name: Rodrun LC) -5000, liquid crystal transition temperature 280
° C) at the ratio shown in Table 7 below, melt-kneaded with a twin-screw kneading extruder (trade name: PCM-30, manufactured by Ikegai Kiko Co., Ltd.), extruded from a 3 mm diameter strand die, and water-cooled.
By pelletizing with a pelletizer, liquid crystal resin /
A polypropylene composite pellet was obtained. In this case, the barrel temperature and the mold temperature were both set to 290 ° C. The composite pellet was broken, and the fracture surface was observed with a scanning electron microscope. As a result, it was confirmed that the liquid crystal resin was fibrillated and dispersed.

Next, the composite pellets and a silane crosslinkable polypropylene (trade name: LINKRON X, manufactured by Mitsubishi Chemical Corporation)
PM800HM, melting temperature 167 ° C., MI = 10 g / 1
0 minutes), a silane crosslinking catalyst master batch (manufactured by Mitsubishi Chemical Corporation, trade name: PZ-10S), and azodicarbonamide (manufactured by Otsuka Chemical Co., trade name: Uniform AZ SO-2)
0, and a decomposition temperature of 201 ° C.) at a ratio shown in Table 8 below, and a blow molding machine (manufactured by Nippon Steel Corporation, product number: JEB-7)
), And the resin discharge portion was extruded into a parison shape from a mold having a diameter of 50 mm, and was shaped using a blow forming mold shown in FIG. At this time, the barrel and the mold were both set at a temperature of 180 ° C. In the blow molding, compressed air having an air pressure of 5 kg / cm ² was used, the temperature of the blow mold was adjusted to 25 ° C., and the air blowing time was 35 ° C.
Seconds.

After blowing air, release the blow mold,
The effervescent vehicle was taken out. The foamable shaped body obtained as described above was immersed in hot water at 100 ° C. for 2 hours to crosslink.

The crosslinked foamable shaped body was placed on a sheet made of tetrafluoroethylene, placed in a heating oven adjusted to a temperature of 230 ° C., and allowed to stand for 10 minutes to foam by heating. After the heating and foaming, the foam was taken out of the heating oven, allowed to cool, and the shaped foam was solidified.

The deviation of the radius of curvature and the radius of curvature of the shaped foam obtained as described above from uniform foaming, and the deviation of the foaming ratio of the shaped foam from uniform foaming in each of the vertical, horizontal and height directions. Was evaluated in the same manner as in Example 1 at the portions corresponding to the positions indicated by A and B in FIG.

(Comparative Example 11) Except that the composition of the resin used was changed as shown in Tables 7 and 8 below,
A shaped foam was obtained and evaluated in the same manner as in Example 9.

[0128]

[Table 7]

[0129]

[Table 8]

[0130]

[Table 9]

[0131]

[Table 10]

As is clear from Tables 7 to 10, Comparative Example 6 in which no liquid crystal resin was used, Comparative Example 7 in which the compounding ratio of the liquid crystal resin was too low, and Comparative Example in which the compounding ratio of the thermal decomposition type foaming agent was too small. According to Examples 6 and 7, as compared with Comparative Example 8 and too many Comparative Examples 9, the deviation from the uniform foaming of the radius of curvature was significantly reduced, and each of the shaped foam in the vertical direction, the horizontal direction, and the height direction. It can be seen that the deviation from the uniform foaming in Example 1 was also significantly reduced.

Similarly, Comparative Example 6 using no liquid crystal resin
On the other hand, in the corresponding Example 8, the deviation of the radius of curvature from the uniform foaming is remarkably small, and the deviation of the shaped foam from the uniform foaming in each of the vertical, horizontal, and height directions is very small.

Further, Comparative Example 1 in which no liquid crystal resin was used
Compared with Example 1, in the corresponding Example 9, the deviation from the uniform foaming of the radius of curvature of the shaped foam curved part and the deviation from the uniform foaming in the vertical, horizontal, and height directions of the shaped foam are also different. It turns out that it has become very small.

[0135]

As described above, in the method for producing a thermoplastic shaped foam according to each of the first to fourth aspects of the present invention, a fibril-like liquid crystal resin, a thermoplastic resin and a pyrolytic foaming agent are used. After shaping the foamable resin composition containing the above specific ratio, the invention according to claim 1 employs extrusion molding, the invention according to claim 4 employs press molding, and the invention according to claim 5 employs press molding. In the invention according to claim 6, the foamable molded body is obtained by blow molding or vacuum or pressure forming, and the obtained foamable molded body is heated and foamed to obtain a molded foam. .

According to the second aspect of the present invention, when the foamable resin composition containing a thermoplastic resin, a liquid crystal resin and a pyrolytic foaming agent is primarily foamed, the liquid crystal resin is fibrillated to form a foamable shaped body. And heating the foamable shaped body to obtain a shaped foam.

In the third aspect of the present invention, the temperature of the foamable resin composition at the time of extrusion is set to a temperature exceeding the liquid crystal transition point of the liquid crystal resin. Since the molten resin can be smoothly extruded and has a temperature of 300 ° C. or less, the fibrillated liquid crystal resin is immediately cooled while maintaining a high aspect ratio, and thus is effective with a liquid crystal resin having a high aspect ratio. Thus, it is possible to obtain a shaped foam which is reinforced in a natural manner.

Therefore, in the manufacturing method according to the first to sixth aspects of the present invention, the elongation stress at the time of foaming of the deformable foamed shaped body is increased, the cell membrane is hardly broken at the time of foaming, and the foaming stability is improved. Since the foamability is enhanced, foaming is uniformly performed three-dimensionally while maintaining the shape of the foamable shaped body without being hindered by foaming due to the residual stress of the portion shaped in the foamable shaped body stage. Therefore, since the shape retention during foaming is high, it is possible to provide a deformed foam having a desired shape and a high expansion ratio.

[Brief description of the drawings]

FIG. 1 is a front view of a corrugated mold used to obtain a foamable shaped body in Example 1, as viewed from the ejection opening side.

FIGS. 2A to 2C are a plan view, a side sectional view, and a front sectional view of an upper die of a press die used in Example 5, respectively.

FIGS. 3A to 3C are a plan view, a side cross-sectional view, and a front cross-sectional view of a lower die of a press die used in Example 5, respectively.

FIG. 4 is a perspective view showing a shaped foam obtained in Example 5.

FIGS. 5A to 5C are a plan view, a side cross-sectional view, and a front cross-sectional view for explaining a forming die after air pressure molding used in Example 8.

FIGS. 6A to 6C are a plan view, a side cross-sectional view, and a front cross-sectional view illustrating a blow molding die used in Example 9. FIGS.

[Explanation of symbols]

 1. Mold of irregular shape 2. Shaped foam

Claims (6)

[Claims] 1. A thermal decomposition type foaming agent is added to 100 parts by weight of a resin composition obtained by mixing 0.5 to 30% by weight of a fibril liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin. 0.5 to 30 parts by weight of a foamable resin composition is extruded from a deformed mold at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent. A method for producing a thermoplastic shaped foam, characterized in that a shaped foam is obtained by heating to a temperature not lower than the decomposition temperature of the agent. 2. A heat-decomposable foaming agent of 0.5 to 30% by weight is added to 100 parts by weight of a resin composition obtained by mixing 0.5 to 30% by weight of a liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin. 30 parts by weight of the foamable resin composition is extruded from a deformed mold at a temperature equal to or higher than the decomposition temperature of the thermal decomposition type foaming agent and higher than the liquid crystal transition point of the liquid crystal resin. A method for producing a thermoplastic shaped foam, comprising obtaining a shaped foam by reheating to a temperature not lower than the decomposition temperature of the agent. 3. Extrusion of the foamable resin composition from a deformed mold at a temperature not lower than the decomposition temperature of the thermal decomposition type foaming agent but exceeding the transition point of the liquid crystal resin and not higher than 300 ° C. The method for producing a thermoplastic shaped foam according to claim 2, wherein the foam is discharged. 4. A thermal decomposition type foaming agent of 0.5 to 30% by weight based on 100 parts by weight of a resin composition containing 0.5 to 30% by weight of a fibril-like liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin.
A sheet-like foamable resin composition obtained by mixing 30 parts by weight is shaped by press molding at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent. A method for producing a thermoplastic shaped foam, characterized in that a shaped foam is obtained by heating to a temperature not lower than the decomposition temperature of a mold blowing agent. 5. A thermally decomposable foaming agent of 0.5 to 30% by weight per 100 parts by weight of a resin composition containing 0.5 to 30% by weight of a fibril liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin.
After forming the sheet-shaped foamable resin composition obtained by mixing 30 parts by weight at a temperature not lower than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent, by vacuum forming or pressure forming, heat is applied. A method for producing a thermoplastic shaped foam, wherein a shaped foam is obtained by heating the foam to a temperature equal to or higher than the decomposition temperature of the decomposable foaming agent. 6. A thermal decomposition type foaming agent of 0.5 to 30% by weight based on 100 parts by weight of a resin composition containing 0.5 to 30% by weight of a fibril liquid crystal resin and 70 to 99.5% by weight of a thermoplastic resin.
The foamable resin composition obtained by mixing 30 parts by weight is extruded in a parison shape at a temperature equal to or higher than the melting temperature of the thermoplastic resin and lower than the decomposition temperature of the pyrolytic foaming agent, and the deformed shaped body obtained by blow molding is heated. A method for producing a thermoplastic shaped foam, wherein a shaped foam is obtained by heating the foam to a temperature equal to or higher than the decomposition temperature of the decomposable foaming agent.