JP2010185057A - Method for producing cyclic olefin-based resin foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a cyclic olefin-based resin foam regardless of heat resistance of the cyclic olefin-based resin. <P>SOLUTION: The cyclic olefin-based resin foam is produced by the method which includes an impregnation step of impregnating the cyclic olefin-based resin with an organic solvent having affinity to the cyclic olefin-based resin, and a foaming step of drying the cyclic olefin-based resin after the impregnation step at a drying temperature at which saturated vapor pressure of the organic solvent is 100-200 mHg. The drying temperature is set to be lower by 30-80&deg;C than the glass transition point of the cyclic olefin-based resin. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a foam using a cyclic olefin resin.

  Conventionally, polyethylene, polystyrene, and the like are known as a resin material used for manufacturing a resin foam. However, the foam obtained by using such a resin material may not have sufficient heat resistance, chemical resistance and the like for use, and has been demanded for improvement.

  Therefore, a foam using a cyclic olefin resin is known. The cyclic olefin-based resin is a resin having a cyclic olefin skeleton in the main chain. Cyclic olefin resin is highly transparent, low birefringence, high heat distortion temperature, light weight, dimensional stability, low water absorption, hydrolysis resistance, chemical resistance, low dielectric constant, low dielectric loss, environment It is a resin with many features such as no loading substances. Such cyclic olefin-based resins having many characteristics are used in various fields where these characteristics are required. In addition to the above characteristics, the cyclic olefin-based resin has excellent foam moldability and excellent side pressure resistance derived from high rigidity. For this reason, cyclic olefin resin is suitable as a resin material used for manufacture of a foam.

  Incidentally, the foam is required to have a high expansion ratio. This is because if the expansion ratio is high, it is lighter and the amount of the resin material used for manufacturing the foam can be reduced. Further, in order to increase the expansion ratio, it is necessary to be a cyclic olefin resin having sufficient mechanical strength.

Thus, for example, light weight foam is disclosed that the foam density using a cyclic olefin resin 0.05 g / cm ³ from 0.02 g / cm ³ (Patent Document 1).

JP 2007-145987 A

  As described above, research on foams using cyclic olefin-based resins has been actively conducted. However, a cyclic olefin resin foam having a high expansion ratio using a cyclic olefin resin having high heat resistance has not been obtained.

  The present invention has been made to solve the above-described problems, and its object is to provide a method for producing a cyclic olefin resin foam regardless of the heat resistance of the cyclic olefin resin. There is.

  The present inventors paid attention to producing a cyclic olefin-based resin foam by a method different from the conventional method based on extrusion foaming, and conducted intensive studies to solve the above-mentioned problems. As a result, the impregnation step of impregnating the cyclic olefin resin with an organic solvent having affinity for the cyclic olefin resin, and the saturated vapor pressure of the organic solvent from 100 mHg to 200 mHg after the impregnation step. A foaming step of drying at a drying temperature, and producing the cyclic olefin resin foam by a method in which the drying temperature is 30 ° C. to 80 ° C. lower than the glass transition point of the cyclic olefin resin. Thus, the inventors have found that the above-described problems can be solved, and have completed the present invention. More specifically, the present invention provides the following.

  (1) An impregnation step of impregnating a cyclic olefin resin with an organic solvent having affinity for the cyclic olefin resin, and a saturated vapor pressure of the organic solvent from 100 mmHg to 200 mmHg after the impregnation step. And a foaming step of drying at a drying temperature, wherein the drying temperature is 30 to 80 ° C. lower than the glass transition point of the cyclic olefin resin.

(2) The method for producing a cyclic olefin resin foam according to (1), wherein the solubility parameter of the organic solvent is 20 (J / cm ³ ) ^1/2 or less.

  (3) The said foaming process is a manufacturing method of the cyclic olefin resin foam as described in (1) or (2) performed at normal temperature and a normal pressure.

  According to the present invention, a cyclic olefin resin foam can be produced by firing a cyclic olefin resin under specific conditions using a specific organic solvent, regardless of the heat resistance of the cyclic olefin resin. .

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. . In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

<Cyclic olefin resin>
The cyclic olefin resin used in the present invention contains a cyclic olefin component as a copolymerization component, and is not particularly limited as long as it is a polyolefin resin containing a cyclic olefin component in the main chain. For example, an addition polymer of a cyclic olefin or a hydrogenated product thereof, an addition copolymer of a cyclic olefin and an α-olefin, or a hydrogenated product thereof can be used.

  Moreover, as cyclic olefin resin which contains the cyclic olefin component used for this invention as a copolymerization component, what grafted and / or copolymerized the unsaturated compound which has a polar group further to the said polymer is included.

  Examples of the polar group include a carboxyl group, an acid anhydride group, an epoxy group, an amide group, an ester group, and a hydroxyl group. Examples of the unsaturated compound having a polar group include (meth) acrylic acid and maleic acid. Acid, maleic anhydride, itaconic anhydride, glycidyl (meth) acrylate, alkyl (meth) acrylate (carbon number 1-10) ester, maleic acid alkyl (carbon number 1-10) ester, (meth) acrylamide, (meta ) 2-hydroxyethyl acrylate.

  In the present invention, an addition copolymer of a cyclic olefin and an α-olefin or a hydrogenated product thereof can be preferably used.

  Moreover, as the cyclic olefin-based resin (A) containing the cyclic olefin component used in the present invention as a copolymerization component, it is also possible to use a commercially available resin. Examples of the commercially available cyclic olefin-based resin (A) include TOPAS (registered trademark) (Topas Advanced Polymers), Apel (registered trademark) (Mitsui Chemicals), Zeonex (registered trademark) (Nippon Zeon Corporation). Product), Zeonoa (registered trademark) (manufactured by Nippon Zeon Co., Ltd.), Arton (registered trademark) (manufactured by JSR Corporation), and the like.

（式中、Ｒ^１〜Ｒ^１２は、それぞれ同一でも異なっていてもよく、水素原子、ハロゲン原子、及び、炭化水素基からなる群より選ばれるものであり、
Ｒ^９とＲ^１０、Ｒ^１１とＲ^１２は、一体化して２価の炭化水素基を形成してもよく、
Ｒ^９又はＲ^１０と、Ｒ^１１又はＲ^１２とは、互いに環を形成していてもよい。
また、ｎは、０又は正の整数を示し、
ｎが２以上の場合には、Ｒ^５〜Ｒ^８は、それぞれの繰り返し単位の中で、それぞれ同一でも異なっていてもよい。） The addition copolymer of cyclic olefin and α-olefin preferably used in the composition of the present invention is not particularly limited. Particularly preferred examples include a copolymer containing [1] an α-olefin component having 2 to 20 carbon atoms and [2] a cyclic olefin component represented by the following general formula (I).

(Wherein R ^{1 to} R ¹² may be the same as or different from each other, and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group;
R ⁹ and R ¹⁰ , R ¹¹ and R ¹² may be integrated to form a divalent hydrocarbon group,
R ⁹ or R ¹⁰ and R ¹¹ or R ¹² may form a ring with each other.
N represents 0 or a positive integer;
When n is 2 or more, R ^{5 to} R ⁸ may be the same or different in each repeating unit. )

[[1] α-olefin component having 2 to 20 carbon atoms]
The C2-C20 alpha-olefin used as the copolymerization component of the addition polymer of the cyclic olefin component preferably used for this invention and other copolymerization components, such as ethylene, is not specifically limited. For example, the thing similar to Unexamined-Japanese-Patent No. 2007-302722 can be mentioned. These α-olefin components may be used alone or in combination of two or more. Of these, ethylene is most preferably used alone.

[[2] Cyclic olefin component represented by formula (I)]
In the addition polymer of the cyclic olefin component preferably used in the present invention and another copolymer component such as ethylene, the cyclic olefin component represented by the general formula (I) serving as the copolymer component will be described.

R ^{1 to} R ¹² in the general formula (I) may be the same or different and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group.

Specific examples of R ^{1 to} R ⁸ include, for example, a hydrogen atom; a halogen atom such as fluorine, chlorine and bromine; a lower alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group. May be different from each other, may be partially different, or all may be the same.

Specific examples of R ^{9 to} R ¹² include, for example, hydrogen atom; halogen atom such as fluorine, chlorine, bromine; methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, hexyl group, stearyl. Alkyl group such as cyclohexyl group; cycloalkyl group such as cyclohexyl group; substituted or unsubstituted aromatic hydrocarbon group such as phenyl group, tolyl group, ethylphenyl group, isopropylphenyl group, naphthyl group, anthryl group; benzyl group, phenethyl And an aralkyl group in which an aryl group is substituted with an alkyl group, and the like. These may be different from each other, may be partially different, or all may be the same.

Specific examples of the case where R ⁹ and R ¹⁰ or R ¹¹ and R ¹² are integrated to form a divalent hydrocarbon group include, for example, alkylidene groups such as an ethylidene group, a propylidene group, and an isopropylidene group. Can be mentioned.

When R ⁹ or R ¹⁰ and R ¹¹ or R ¹² form a ring with each other, the formed ring may be monocyclic or polycyclic, or may be a polycyclic ring having a bridge. , A ring having a double bond, or a ring composed of a combination of these rings may be used. Moreover, these rings may have a substituent such as a methyl group.

  Specific examples of the cyclic olefin component represented by the general formula (I) include those similar to those described in JP-A-2007-302722.

  These cyclic olefin components may be used singly or in combination of two or more. Among these, it is preferable to use bicyclo [2.2.1] hept-2-ene (common name: norbornene) alone.

  The glass transition point of the cyclic olefin resin is not particularly limited. This is because the present invention is characterized in that various types of cyclic olefin resins are made into excellent cyclic olefin resin foams regardless of heat resistance. When selecting an organic solvent to be described later, by selecting an organic solvent having a saturated vapor pressure of 100 mmHg to 200 mmHg within a temperature range of 30 ° C to 80 ° C lower than the glass transition point of the cyclic olefin resin, Regardless of the heat resistance of the cyclic olefin resin, a cyclic olefin resin foam can be produced. In addition, the glass transition point (Tg) employ | adopts the value measured by DSC method (method of JISK7121) on the temperature increase rate of 10 degree-C / min conditions.

  According to the present invention, various cyclic olefin-based resins can be foamed regardless of the heat resistance of the cyclic olefin-based resin and the like, and the cyclic olefin-based resin was measured at 190 ° C. and the winding speed was 15 m / min. The melt tension is preferably from 25 mN to 60 mN. If the cyclic olefin resin has a melt tension of 25 mN or more, it is preferable because bubbles are difficult to break, and if the cyclic olefin resin has a melt tension of 60 mN or less, it is preferable because of the growth of the bubble size. A more preferable range of the melt tension of the cyclic olefin-based resin is 30 mN to 50 mN.

  The cyclic olefin resin used in the present invention preferably has a melt viscosity of 50 Pa · s to 500 Pa · s measured at 260 ° C. and a shear rate of 1216 / s in accordance with ISO11443. If the melt viscosity of the cyclic olefin-based resin is less than 50 Pa · s, it becomes difficult to obtain a foam by cracking the bubbles, and if the melt viscosity of the cyclic olefin-based resin exceeds 500 Pa · s, beads and a molded body before foaming are obtained. Becomes difficult. A more preferable range of melt viscosity is 80 Pa · s to 250 Pa · s.

  [1] A method for polymerizing an α-olefin component having 2 to 20 carbon atoms and a [2] cyclic olefin component represented by formula (I) and a method for hydrogenating the obtained polymer are particularly limited. Instead, it can be carried out according to known methods. Random copolymerization or block copolymerization may be used, but random copolymerization is preferred.

  The polymerization catalyst used is not particularly limited, and can be obtained by a known method using a conventionally known catalyst such as a Ziegler-Natta, metathesis, or metallocene catalyst.

  Examples of the metathesis catalyst include molybdenum or tungsten-based metathesis catalysts (for example, described in JP-A Nos. 58-127728 and 58-129003) as a catalyst for ring-opening polymerization of cycloolefin. In addition, the polymer obtained by the metathesis catalyst uses an inorganic carrier-supported transition metal catalyst or the like, and 90% or more of the main chain double bond and 98% or more of the carbon-carbon double bond in the side chain aromatic ring are hydrogenated. It is preferable to add.

[Other copolymer components]
The cyclic olefin-based resin (A) does not impair the object of the present invention other than [1] the α-olefin component having 2 to 20 carbon atoms and [2] the cyclic olefin component represented by the general formula (I). In the range, other copolymerizable unsaturated monomer components may be contained as required.

  The unsaturated monomer that may be optionally copolymerized is not particularly limited, and examples thereof include hydrocarbon monomers containing two or more carbon-carbon double bonds in one molecule. Can be mentioned. Specific examples of the hydrocarbon-based monomer having two or more carbon-carbon double bonds in one molecule include those similar to those described in JP-A-2007-302722.

<Organic solvent>
The organic solvent used for the production of the cyclic olefin resin foam of the present invention varies depending on the cyclic olefin resin used. Specifically, the usable organic solvent is an organic solvent that has a saturated vapor pressure of 100 mmHg to 200 mmHg within a range of 30 ° C. to 80 ° C. lower than the glass transition point of the cyclic olefin resin, and is compatible with the cyclic olefin resin. Organic solvent. By selecting such an organic solvent and impregnating the cyclic olefin resin with the selected organic solvent, the apparent glass transition point of the cyclic olefin resin becomes lower than the drying temperature described later. Thereafter, when the solvent impregnated in the cyclic olefin resin escapes from the cyclic olefin resin, the cyclic olefin resin foams. It is speculated that such foaming of the cyclic olefin resin can be applied to various cyclic olefin resins regardless of the heat resistance of the cyclic olefin resin because the resin is plasticized by a solvent.

  The apparent glass transition point of the cyclic olefin resin is measured by the same method as the glass transition point of the cyclic olefin resin. Moreover, it is preferable that the apparent glass transition point of cyclic olefin resin is the range of +/- 10 degreeC of drying temperature. If it is in the said temperature range, it is preferable for the reason that an expansion ratio becomes large.

  In the present invention, an organic solvent having a saturated vapor pressure of 100 mmHg to 200 mmHg in a range 30 to 80 ° C. lower than the glass transition point of the cyclic olefin resin is used. If it is less than 100 mmHg, it is not preferable because the evaporation rate is too high, and if it exceeds 200 mmHg, it is not preferable because the solvent remains in the foam.

  The organic solvent needs to have a saturated vapor pressure in the above range within a range of 30 ° C. to 80 ° C. lower than the glass transition point of the cyclic olefin resin. It is preferable that the organic solvent satisfy the saturated vapor pressure range within a temperature range of 30 ° C. or lower than the glass transition point of the cyclic olefin resin because the foam does not shrink after foaming. It is preferable to satisfy the above range of the saturated vapor pressure at a temperature of 80 ° C. or lower than the transition point because the expansion ratio is increased.

The phrase “having affinity for the cyclic olefin resin” means an organic solvent that dissolves the cyclic olefin resin. The degree of affinity of the organic solvent for the cyclic olefin resin is not particularly limited, but the solubility parameter of the organic solvent is preferably 20 (J / cm ³ ) ^1/2 or less. If the solubility parameter of the organic solvent is 20 (J / cm ³ ) ^1/2 or less, the organic solvent is appropriately impregnated into the cyclic olefin resin, and the apparent glass transition point of the cyclic olefin resin is lowered to an appropriate range. The cyclic olefin resin is moderately flexible in the drying temperature range. As a result, it is preferable because, during drying, the organic solvent tends to foam when it escapes from the cyclic olefin resin.

Any organic solvent as described above can be used. Examples of the organic solvent that can be used for the production of the cyclic olefin resin foam of the present invention include n-hexane, cyclohexane, toluene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone, chloroform, methylene chloride, ethylene chloride, acetone, and cyclohexanone. , Dioxane, n-butanol, isopropanol, ethanol, methanol and the like. Among these, n-hexane, cyclohexane, toluene, ethyl acetate, tetrahydrofuran, benzene, methyl ethyl ketone, chloroform, and methylene chloride are preferable. This is because the organic solvent has a solubility parameter of 20 (J / cm ³ ) ^1/2 or less.

<Method for Producing Cyclic Olefin Resin Foam>
The method for producing a cyclic olefin resin foam of the present invention comprises an impregnation step of impregnating a cyclic olefin resin with an organic solvent having an affinity for the cyclic olefin resin, and the cyclic olefin resin after the impregnation step, And a foaming step of drying at a drying temperature at which the saturated vapor pressure of the organic solvent becomes 100 mmHg to 200 mmHg. Hereinafter, an example of the manufacturing method of the cyclic olefin resin foam of this invention is demonstrated.

[Molding process]
The molding step is a step of molding a desired cyclic olefin resin. The molding method is not particularly limited, and examples thereof include various molding methods such as compression molding, transfer molding, injection molding, extrusion molding, and blow molding. By molding the cyclic olefin resin by the molding method as described above, a cyclic olefin resin molded product can be obtained.

  The cyclic olefin resin used as a raw material may be a blend of a plurality of cyclic olefin resins, or may be a blend of a resin other than a cyclic olefin resin and a cyclic olefin resin. In addition, additives such as nucleating agent, carbon black, pigments such as inorganic fired pigments, antioxidants, stabilizers, plasticizers, lubricants, mold release agents, and flame retardants are added to the resin to achieve desired characteristics. It may be given.

[Impregnation process]
The impregnation step is a step of impregnating the cyclic olefin-based resin molded product molded in the molding step with an organic solvent having affinity. By impregnating the cyclic olefin-based resin molded product with the organic solvent, the apparent glass transition point of the cyclic olefin-based resin is lowered, and the cyclic olefin-based resin molded product exhibits flexibility at a drying temperature described later.

  The present invention impregnates a cyclic olefin-based resin molded product with an organic solvent, develops flexibility in the cyclic olefin-based resin molded product, and removes the organic solvent from the cyclic olefin-based resin molded product in the foaming step. Foam the resin molded product.

[Foaming process]
The foaming step is a step of drying the cyclic olefin-based resin after the impregnation step at a drying temperature at which the saturated vapor pressure of the organic solvent becomes 100 mmHg to 200 mmHg. As described above, the cyclic olefin-based resin molded article is impregnated with an organic solvent to lower the apparent glass transition point and to impart flexibility. In this step, when the organic solvent evaporates from the cyclic olefin resin molded product during drying, the cyclic olefin resin molded product foams. At the same time, in the process where the organic solvent escapes from the cyclic olefin resin molding by evaporation, the apparent glass transition point of the cyclic olefin resin approaches the glass transition point of the original cyclic olefin resin, When the apparent glass transition point of the resin exceeds the drying temperature, the flexibility imparted to the cyclic olefin resin molded article is lost, and a cyclic olefin resin foam is obtained. As described above, the drying temperature for drying the cyclic olefin-based resin molded article impregnated with the organic solvent in the foaming step needs to be performed at a temperature 30 to 80 ° C. lower than the glass transition point of the cyclic olefin-based resin.

  The foaming step can be performed by applying pressure when a desired organic solvent has been determined, but when an organic solvent to be used is not determined, an organic solvent that can be used at normal pressure is used. It is preferable to select and foam at normal pressure. This is because the cyclic olefin resin foam can be easily produced by foaming the cyclic olefin resin molded product at normal pressure.

  Further, when the glass transition point of the cyclic olefin resin to be foamed is in the range of about 50 ° C. to about 100 ° C., the foaming step can be performed at normal temperature and normal pressure by selecting an organic solvent. If the foaming step can be performed at normal temperature and normal pressure, it is preferable because the cyclic olefin resin foam can be more easily produced.

[Other methods]
The production of the cyclic olefin resin foam of the present invention includes a step of impregnating a cyclic olefin resin with the organic solvent as described above, and evaporating the organic solvent from the cyclic olefin resin impregnated with the organic solvent. What is necessary is just to be equipped with the foaming process of foaming a system resin. For example, the manufacturing method of the cyclic olefin resin foam of this invention can also be implemented by bead foaming method. Specifically, first, resin beads of a cyclic olefin resin are prepared, then, the resin beads of the cyclic olefin resin are impregnated with an organic solvent to perform primary foaming, and finally, the cyclic olefin resin of the primary foamed resin is produced. A cyclic olefin-based resin foam can be produced by placing resin beads in a mold and simultaneously performing molding and secondary foaming.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

<Material>
Cyclic olefin resin pellets: TOPAS 8007F-04 (manufactured by Polyplastics), glass transition point 80 ° C
Organic solvent 1: chloroform, saturated vapor pressure at 23 ° C., 178 mmHg, solubility parameter 19 (J / cm ³ ) ^1/2
Organic solvent 2: cyclohexane, saturated vapor pressure at 23 ° C. 89 mmHg, solubility parameter 16.8 (J / cm ³ ) ^1/2

<Example 1>
0.1 g of the above cyclic olefin-based resin pellets were added to 10 ml of chloroform and heated to 50 ° C. with stirring to dissolve the pellets. Further, while continuing stirring, the temperature was raised to a temperature at which chloroform boiled, the solvent was concentrated, and chloroform was distilled off until a solid of a cyclic olefin resin was finally obtained. When the weight of this resin solid was measured, the solvent impregnation amount was 0.2 g. This resin solid was molded into a hemisphere with a diameter of 5 mm on the bottom and placed in the center of the evaporating dish and allowed to stand for 48 hours at a room temperature of 23 ° C. and a humidity of 50%.

<Example 2>
1 g of the above cyclic olefin resin pellets were added to 100 ml of chloroform, and the pellets were dissolved by heating to 50 ° C. with stirring. Further, while continuing stirring, the temperature was raised to a temperature at which chloroform boiled, the solvent was concentrated, and chloroform was distilled off until a solid of a cyclic olefin resin was finally obtained. When the weight of this resin solid was measured, the solvent impregnation amount was 2 g. This resin solid was molded into a flat disk shape (hajiki shape) with a diameter of 2 cm at the bottom and a height of about 8 mm, placed in the center of the evaporating dish and left at room temperature 23 ° C. and humidity 50% for 48 hours. Foaming to a diameter of 6 cm and a height of 3 cm.

<Comparative Example 1>
To 10 ml of cyclohexane, 0.1 g of the above cyclic olefin resin pellets was added and heated to 50 ° C. with stirring to dissolve the pellets. Furthermore, while continuing stirring, the temperature was raised to a temperature at which cyclohexane boils, the solvent was concentrated, and finally cyclohexane was distilled off until a solid of a cyclic olefin resin was obtained. When the weight of this resin solid was measured, the solvent content was 0.1 g. This resin solid was molded into a hemisphere with a diameter of 5 mm on the bottom and placed in the center of the evaporating dish and left at room temperature 23 ° C. and 50% humidity for 48 hours. The solvent completely evaporated and the weight of the resin solid Returned to 0.1 g, but the size of the hemisphere shrunk, and no bubbles were found inside the solid.

Claims (3)

An impregnation step of impregnating the cyclic olefin resin with an organic solvent having an affinity for the cyclic olefin resin;
A foaming step of drying the cyclic olefin-based resin after the impregnation step at a drying temperature at which the saturated vapor pressure of the organic solvent becomes 100 mmHg to 200 mmHg,
The said drying temperature is a manufacturing method of the cyclic olefin resin foam whose temperature is 30 to 80 degreeC lower than the glass transition point of the said cyclic olefin resin. The method for producing a cyclic olefin-based resin foam according to claim 1, wherein the solubility parameter of the organic solvent is 20 (J / cm ³ ) ^1/2 or less.   The said foaming process is a manufacturing method of the cyclic olefin resin foam of Claim 1 or 2 performed at normal temperature and a normal pressure.