JP2002212308A - Phenolic resin molded material and method for molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that although conventionally the phenolic resin is excellent in heat resistance, tenacity, electrical insulation, etc., and its molded product is used widely as an insulating plate, etc., its dimensional stability is inferior to those of inorganic materials, metals, etc., and therefore in the case of using the molded material by conjugating with other materials, inferiorities such as bending, twisting, cracking, etc., remain potentially. SOLUTION: This method for molding is provided by using an alkylene oxide derivative as a modifying agent, dissolving it uniformly in the resin liquid, separating it from the resin layer along with its curing and forming a uniformly dispersed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenolic resin-based molding material, and more particularly to a phenolic resin molded product using a resole-based phenolic resin and having excellent dimensional stability, and a method of molding the same.

[0002]

2. Description of the Related Art Conventionally, phenolic resins have been known for their heat resistance, toughness,
Because of its excellent properties such as hardness and electrical insulation, it is used in a wide range of fields such as insulating boards, decorative boards, molded parts, and adhesives.

[0003]

However, a molded article using a phenolic resin has a drawback that its dimensional stability is inferior to inorganic materials such as glass, metals, and the like. Defects such as cracks, peeling of the bonded portion, etc. were potentially left. In particular, when used in combination with other materials, the above-mentioned defects become remarkable, so that improvement has been demanded. Conventionally, as a method of reducing the dimensional change, there is a method of blending a large amount of an inorganic filler or the like, but there is a problem that the strength of a molded product is reduced, and improvement by another method has been required.

[0004]

According to the present invention, as a result of intensive studies to solve the above-mentioned problems, it has been found that the phenol resin is blended with a certain type of modifier to improve the dimensional stability. Alternatively, it has been found that the effect of reducing the color tone of the molding material over time and reducing the color tone change over time can be obtained.

[0005] As a result of extensive studies on modifying agents capable of realizing such characteristics, it has been found that an alkylene oxide derivative having a hydroxyl group is mixed with a resole phenolic resin as a modifying agent to obtain a modified resin composition. It is confirmed that a modifier that is dissolved in the state, separates from the resin as the curing progresses, and forms a structure uniformly dispersed in the cured product has such an effect, and has led to the present invention. Things. Illustrative examples of the alkylene oxide derivative include polyethylene glycol,
Polypropylene glycol, polybutylene glycol,
Examples include polyethylene glycol glyceryl ether and polypropylene glycol glyceryl ether. Also,
The alkylene oxide derivative can be phase-separated and uniformly dispersed by adding a compound having polymerizability in the molecule to a resol-based phenol resin and polymerizing it in a curing process to increase the molecular weight. Examples of these include polyalkylene glycol (meth) acrylates such as polyethylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate, and allylated polyethers such as polyethylene glycol allyl ether and polypropylene glycol allyl ether. .

As the compound that separates and disperses during the curing process of the resol-based phenolic resin, the compound is more hydrophobic and the phase separation is easier as the molecular weight is higher. However, if the hydrophobicity and the molecular weight become higher than a certain level, they may become insoluble in the resol-based phenol resin solution, or may exude in a liquid state without separating into a uniform dispersion state even though they are separated during the curing process. These phenomena differ depending on the reaction ratio of phenol and formaldehyde, the reaction catalyst, for example, compounds that co-condensate such as alkylphenols and amino compounds, modifiers such as plasticizers added, and molding conditions. It is necessary to adjust and select the kind, molecular weight and addition amount of the alkylene oxide derivative according to the characteristics.

[0007] In order to realize the object of the present invention, in the state of the resin liquid, the resin and the modifier are dissolved,
It is necessary that the modifier is separated and uniformly dispersed in the cured resin. The purpose cannot be achieved if the resin is uniformly dissolved in the cured resin. In the present invention, the modifier is separated in the cured resin, as a determination of whether or not dispersed, whether or not the transparent uniform state at the time of curing,
The determination can be made based on whether the milky milky state or the denaturant is seeping out. If it is in a transparent and uniform state, it is determined that the resin and the modifying agent are uniformly dissolved and cured, and if it is milky, it is determined that they are separated and dispersed. When the denaturing agent is oozing out, it is judged that the denaturing agent is separated without being uniformly dispersed in the cured resin.

In the present invention, the molar ratio of formaldehyde to phenol is desirably 1 to 3, and the additive ratio of the modifier to the solid content of the phenol resin is preferably 5 to 80%.
If the addition rate is 5% or less, the separation and dispersion state cannot be sufficiently obtained, and the object cannot be achieved. If it is 80% or more, the toughness and heat resistance of the phenol resin are impaired, which is not preferable. The modifier may be added at the beginning of the reaction, but may be added after the initial condensate of phenol and formaldehyde is synthesized. The phenol resin can be used alone, but alkylphenols, co-condensates with amino compounds and the like, para-toluenesulfonamide,
It is also applicable to modified resins to which caprolactam or the like is added.

[0009] A laminated sheet will be described as an example of a molded article according to the present invention. The resin material prepared in this manner is processed from fibers such as glass fiber, cellulose fiber, and synthetic fiber into paper, nonwoven fabric, sheet, and woven fabric. A plurality of impregnated sheets impregnated into a substrate such as cloth are laminated, and hot-pressed to finish the laminate. Further, it may be finished by attaching a decorative layer to the surface of the laminated board, or by painting. Or,
On the impregnated sheet prepared in this way, another resin-impregnated sheet, for example, a decorative paper impregnated with a resin such as a melamine resin or an unsaturated polyester resin is laminated and molded, or various decorative sheets are formed. Can be finished as a decorative laminate.

EXAMPLES Synthesis of resole phenolic resin A flask equipped with a stirrer, thermometer and cooling condenser was charged with 1 mol of phenol, 47% formalin aqueous solution 1.3.
A mole (in terms of formaldehyde) was charged, and the pH was adjusted to 8.0 with sodium hydroxide. The reaction solution was heated to 95
The reaction solution is maintained at a temperature of 40 ° C.
It reacted until it became. Thereafter, the mixture was cooled and diluted by adding methanol to obtain a resol type phenol resin (hereinafter referred to as resin A) having a solid content of 50%.

Example 1 An average molecular weight of 4,000 and a hydroxyl value of 26 per 100 parts by weight (hereinafter simply referred to as "parts") of the resin A obtained in the examples.
(KOHmg / g) polypropylene glycol 20
And 20 parts of methanol.
The resin solid which was dropped and cured on a hot plate at 140 ° C. was a uniform milky brown color and did not exude polypropylene glycol.

Example 2 Resin A obtained in Example 2 had an average molecular weight of 15 based on 100 parts.
00, a transparent brown color obtained by adding 20 parts of polypropylene glycol monoallyl ether having a hydroxyl value of 39 (KOH mg / g), 0.75 part of t-butyl peroxy-2-ethylhexanoate as a radical polymerization initiator, and 20 parts of methanol. A resin composition was obtained. The resin composition was dropped on a hot plate at 140 ° C., and the cured resin solid was a uniform milky brown color, with no bleeding of polypropylene glycol monoallyl ether.

Comparative Example 1 Resin A obtained in the Example was used as Comparative Example 1 as it was. The resin of Comparative Example 1 was dropped on a hot plate at 140 ° C., and the cured resin solid had a uniform, transparent and dry color.

Comparative Example 2 A transparent brown comparative example 2 was obtained by adding 20 parts of polypropylene glycol having an average molecular weight of 400 and a hydroxyl value of 279 (KOH mg / g) to 100 parts of the resin A obtained in Example and 20 parts of methanol. Was obtained. The resin solid obtained by dropping the resin composition on a hot plate at 140 ° C. and hardening had a uniform transparent dry color and did not bleed.

Using the resin compositions of the above Examples and Comparative Examples, molded articles were molded as follows. (Blending) Resin A and composition 100 parts by weight Calcium carbonate 200 parts by weight This blend was diluted with methanol to obtain a slurry for impregnation coating. The slurry was weighed 75 g / m 2 and had a density of 0.15.
g / m3 glass fiber nonwoven fabric was impregnated and then dried to obtain a prepreg sheet for lamination having a basis weight of 900 g / m2. 7. Laminate 7 prepreg sheets at 150 ° C, 9.
Molding was performed at 8 MPa (100 kg / cm 2) for 30 minutes to obtain a laminated plate having a thickness of 3 mm. Table 1 shows the dimensional change rate and the degree of color tone change of the laminate.

[0016]

[Table 1] (Measurement method) * Dimensional change rate Elongation + according to JISK 6902
Expressed as the total shrinkage. (Elongation) Measured by leaving it in a thermo-hygrostat at 40 ± 2 ° C. and 90-95% relative humidity for 96 hours. (Shrinkage) Measured by leaving it in a constant temperature dryer at 70 ± 2 ° C for 24 hours. * Color difference The Lab of the molded article and the molded article left for 96 hours in a constant temperature and humidity apparatus at 40 ± 2 ° C. and a relative humidity of 90 to 95% was measured with a spectrophotometer, and the color difference ΔE was calculated based on the Hunter color difference equation. Ask for. * Boiling resistance According to JISK6902. 5
After boiling the 0 mm square test piece for 2 hours, it is determined whether or not the test piece has delaminated and the filler has not fallen off. * Bending strength According to JISK 6902. * Flexural modulus According to JISK6902.

In the molded article according to the present invention, since the modifier is separated and dispersed in the cured phenol resin, the shrinkage and expansion stress of the phenol resin layer caused by the environmental change is transmitted throughout. I can't. Therefore, the dimensional stability is greatly improved. Therefore, when the molded product according to the present invention, for example, a laminate is integrally bonded to another base material such as a mortar base with an adhesive, peeling of the adhesive layer caused by a dimensional change of the laminate due to environmental change,
Effects such as a reduction in warpage of the base material and generation of cracks can be obtained. For this reason, problems such as peeling, warping, and cracks, which often occur in the case of compounding with various base materials, can be eliminated, and the device can be used with confidence. Further, if it is used as a molding material such as an electric insulating material, the quality can be improved without problems such as improvement of dimensional stability and deviation. Furthermore,
Due to the structure in which the modifier is separated and dispersed around the phenol resin, the color difference blur is reduced and the appearance is improved.

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Claims (6)

[Claims] 1. A phenolic resin molded using a condensate of phenol and formaldehyde as a hardening component, wherein a modifier is separated and dispersed in the condensate. Molded product. 2. The molded article according to claim 1, wherein said modifier is an alkylene oxide derivative having a hydroxyl group. 3. The molded article according to claim 1, wherein the condensate is impregnated into a substrate and molded as a laminate. 4. When molding a condensate of phenol and formaldehyde as a curing component, the condensate containing a modifier is cured, and the modifier is separated and dispersed from the cured resin. A method for molding a molded article, characterized by the following. 5. The molding method according to claim 4, wherein the modifying agent is an alkylene oxide derivative having a hydroxyl group. 6. A base material impregnated with a condensate containing a modifier,
The molding method according to claim 4 or 5, wherein the molding is performed as a laminate.