JPH0892431A - Phenol resin composition - Google Patents

Abstract

PURPOSE: To obtain a phenol resin compsn. excellent in flame retardance and heat resistance without detriment to the excellent characteristics inherent in polyethylenes by melt mixing a polyethylene with a specified amt. of a semicured phenol resin powder. CONSTITUTION: This resin compsn. is prepd. by melt mixing and kneading 100 pts.wt. polyethylene and 5-50 pts.wt. semicured phenol resin powder (pref. having an acetone extractable content of 10-90% and a particle size of 1-100μm and comprising, for example, the one prepd. by mixing a novolak phenol resin with a curative and semicuring the mixture by heating and/or the one prepd. by semicuring a resole phenol resin by heating or using an acid). Thus, the excellent characteristics, such as flame retardance and heat resistance, inherent in a phenol resin, are imparted to polyethylene without detriment to the excellent characteristics, such as moldability, and electrical properties, inherent in polyethylenes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin composition which does not impair the properties of polyethylene as a thermoplastic resin and also has good flame retardancy and heat resistance, such as injection molding. It is useful for various molded products obtained by the above, and applications obtained by extrusion molding and the like.

[0002]

2. Description of the Related Art Polyethylene is used in a wide range of fields because of its excellent electrical properties, mechanical properties, processability, and low cost. However, as applications and demands increase, higher performance and special performance are required. When polyethylene is required to be flame-retardant for electric wires, films, sheets, etc., modification is performed by kneading polyethylene with a flame-retardant agent such as antimony trioxide. However, since the compatibility with the flame retardant and the filling property are poor, the kneading operation is difficult, and bloom may occur after commercialization.

Crosslinked polyethylene having improved heat resistance and mechanical strength is used as an electric insulating material. Although polyethylene itself has excellent electrical properties and chemical stability as a cable material, heat resistance and mechanical strength are improved by the chemical crosslinking method using an organic peroxide. However, due to the crosslinking, the excellent workability inherent in thermoplastics is sacrificed, and special materials and chemicals are often required for the crosslinking reaction, and the cost increase cannot be ignored.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a phenol resin composition having excellent flame retardancy and heat resistance, with almost no deterioration of the excellent properties of polyethylene.

The inventors of the present invention have studied the phenol resin for many years, and as a result, have found that polyethylene and a powdery phenol resin semi-cured product are melt-kneaded to give polyethylene a phenol resin having heat resistance and flame retardancy. It was possible to obtain a phenolic resin composition having the characteristics described above. As a result of further diligent study, by using a powdery phenolic resin semi-cured product having an acetone extraction rate of 10 to 90% in the powdery phenolic resin semi-cured product and a powder particle size of 1 to 100 μm, In addition to the above characteristics, they have found that the impact resistance is improved, and have completed the present invention.

[0006]

According to the present invention, 100 parts by weight of polyethylene and 5 to 50 powdery phenol resin semi-cured products are used.
The present invention relates to a phenol resin composition obtained by melt-kneading 1 part by weight, and preferably relates to a phenol resin composition obtained by melt-kneading 100 parts by weight of polyethylene and 5 to 30 parts by weight of a powdery phenol resin semi-cured product. .

The polyethylene used in the present invention is not particularly limited and is generally commercially available.
Here, when the compounding amount of the powdery phenol resin semi-cured product with respect to 100 parts by weight of polyethylene is less than 5 parts by weight, the excellent characteristics of the phenol resin are not exhibited. Also, 5
If the amount exceeds 0 parts by weight, the moldability of polyethylene and the appearance of molded products are impaired.

In the present invention, preferably, a semi-cured phenol resin having an acetone extraction rate of 10 to 90% is crushed and powdered, and the particle size of the powder is 1 to 100 μm.
The powdery phenolic resin semi-cured product is used. Here, if the particle size of the powder is less than 1 μm, the workability during melt-kneading is deteriorated because the particles are extremely fine, and the particle size of the powder is 100 μm.
If it exceeds, the appearance of the molded product may be impaired.

Examples of the phenol resin used when preparing the powdery phenol resin semi-cured product used in the present invention include novolac type phenol resin, resol type phenol resin and benzylic ether type phenol resin. These may be used alone or in combination of two or more. Further, various modified phenolic resins such as rubber modified and alkylbenzene modified can also be used. Preferably, a novolac type phenolic resin and a curing agent are mixed, and a powdery phenolic resin semi-cured product obtained by semi-curing by heating and / or a semi-cured product obtained by semi-curing a resol type phenolic resin by heating or an acid. is there.

The novolac type phenol resin used in the present invention is a reaction of phenols (P) and aldehydes (F) in a compounding molar ratio (F / P) of 0.5 to 1.0. A modified resin is charged in a kettle, and one or more kinds selected from hydrochloric acid, sulfuric acid, phosphoric acid, paratoluenesulfonic acid, benzenesulfonic acid, oxalic acid, maleic acid, formic acid, acetic acid, etc. are added as a resinizing catalyst. When it is obtained, it is further heated after adding a modifier, and after refluxing for an appropriate time, vacuum dehydration or atmospheric dehydration is performed to remove the condensed water produced by the reaction. It can be obtained by a method of removing phenols.

The resol type phenol resin used in the present invention has a blending ratio such that the blending molar ratio (F / P) of phenols (P) and aldehydes (F) is 1.0 to 2.0. In a reaction kettle, as a resinification catalyst, hydroxides or oxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, barium hydroxide and calcium hydroxide, ammonia, triethylamine, etc. When one or more selected from amines is added and a modified resin is obtained, a modifier is further added, followed by heating and refluxing for an appropriate time, and then the condensed water produced by the reaction. It can be obtained by vacuum dehydration or atmospheric dehydration.

The phenols used as raw materials for the phenol resin used in the present invention include phenol, orthocresol, metacresol, paracresol, bisphenol A, bisphenol F, catechol, resorcin, hydroquinone, propylphenol, butylphenol, octylphenol, nonylphenol. It is 1 type (s) or 2 or more types selected from the like. Examples of the aldehydes include formaldehyde, paraformaldehyde, trioxane, acetaldehyde and the like, and one or two or more kinds are appropriately selected from these. In addition, alkylbenzene, cashew oil, terpenes such as rosin, and boric acid are used as the modifier.

As a curing method for preparing the powdery phenol resin semi-cured product used in the present invention, a method of semi-curing with heat and an acid is typically mentioned, and a semi-curing method with heat is particularly preferable. . In the case of a novolac type phenol resin, 1 to 20 parts by weight of a curing agent such as hexamethylenetetramine is added and mixed with 100 parts by weight of the novolac type phenol resin, and the mixture is semi-cured.

In the present invention, the degree of curing of the powdery phenolic resin semi-cured product is shown by the numerical value of the acetone extraction rate measured by the acetone extraction test method. The acetone extraction test is a method of extracting the uncured portion of the phenol resin with a Soxhlet extractor using acetone as a solvent.
Normally, the uncured phenolic resin dissolves in acetone, but it disappears as the curing proceeds. A completely cured powdery phenol resin cured product does not dissolve in acetone at all. That is, the uncured phenol resin has an acetone extraction rate of 100%, and the completely cured phenol resin cured product has an acetone extraction rate of 0%.

The temperature at which the mixture of the novolac type phenol resin and hexamethylenetetramine and the resol type phenol resin are heat-cured is set according to the target degree of curing. That is, when a powdery phenolic resin semi-cured product having a cured structure with an acetone extraction rate of 10 to 90% is produced, the heating temperature is preferably 100 to 140 ° C.

The powdery phenolic resin semi-cured product is pulverized by a hammer mill, a free mill, a pulverizer,
A turbo mill, a jet mill, etc. can be used. The particle size of the powder can be adjusted by the crusher used. In order to obtain a resin powder having a particle size in a specific range, it can be easily obtained by pulverizing and then sieving. On this occasion,
The feed rate of the raw material to the crusher, the rotation speed of the crusher, and the mesh size of the screen of the crusher vary the particle size obtained.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples.
In addition, "parts" and "%" described below indicate "parts by weight" and "% by weight".

I. Synthesis of Phenolic Resin [Synthesis Example 1] 1000 parts of phenol and 8.0 parts of oxalic acid were charged into a reactor equipped with a stirrer, a heat exchanger, and a thermometer. After that, the temperature of the mixed solution was raised to 90 ± 2 ° C., and while maintaining the same temperature and controlling the vacuum degree to 440 Torr, 650 parts of 37% formaldehyde aqueous solution was added to the mixed solution in 3.0 hours. After the addition, the reaction was performed under the same conditions for 3.0 hours after the addition. Subsequently, the temperature of the reaction solution was raised to 150 ° C. under normal pressure, and the degree of vacuum was 60 Torr.
By keeping the liquid temperature up to 230 ° C while keeping the temperature to be 250 ° C to remove residual water and free monomers, the melting point is 85 ° C.
A novolak type phenol resin (B1) having a free monomer amount of 0.2% at 0 ° C was obtained.

[Synthesis Example 2] 700 parts of phenol and 1% aqueous 37% formaldehyde solution were placed in the same reactor as in Synthesis Example 1.
510 parts and 100 parts of 28% ammonia water were charged. After that, the temperature of the mixed solution was gradually raised, and the mixture was refluxed under reduced pressure at 80 ° C. for 15 minutes. After cooling to an internal temperature of 50 ° C, the mixture was allowed to stand, the separated water was removed, and dehydration under reduced pressure was performed at 60 ° C to give a melting point of 65.
A resol type phenol resin (B2) having a free monomer amount of 1% at 0 ° C was obtained.

II. Preparation of Phenolic Resin Semi-Cured Product [Preparation Example 1] 1000 parts of the novolac-type phenol resin (B1) prepared in Synthesis Example 1 and 100 parts of hexamethylenetetramine were mixed and pulverized, and then heated at 120 ° C for 70 minutes. The semi-cured novolak resin obtained was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The obtained powdery novolak resin semi-cured product (D1) had an average particle size of 30 μm and an acetone extraction rate of 35%.

[Production Example 2] 1000 parts of the novolac type phenol resin (B1) synthesized in Synthesis Example 1 and 100 parts of hexamethylenetetramine were mixed and pulverized, and then heated at 120 ° C for 2 hours. The semi-cured novolak resin obtained was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The obtained powdery novolak resin semi-cured product (D
The average particle size of 2) is 60 μm, and the acetone extraction rate is 1
It was 3%.

[Production Example 3] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 100 ° C for 1 hour. The obtained semi-cured resol resin was roughly crushed with a hammer mill and then finely crushed with a palpelizer. The average particle size of the obtained powdery resol resin semi-cured product (D3) was 30 μm, and the acetone extraction rate was 50%.

[Production Example 4] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 110 ° C for 1 hour. The obtained semi-cured resol resin was roughly crushed with a hammer mill and then finely crushed with a jet mill. The average particle size of the obtained powdery resol resin semi-cured product (D4) is 7
μm, and the acetone extraction rate was 35%.

[Production Example 5] 1,000 parts of the novolac-type phenol resin (B1) synthesized in Synthesis Example 1 and 100 parts of hexamethylenetetramine were mixed and pulverized, and then 110 ° C.
Heated for 1 hour. The semi-cured novolak resin obtained was roughly crushed with a hammer mill and then finely crushed with a pulverizer and a jet mill. The powdery novolak resin semi-cured product (D5) thus obtained had an average particle size of 0.6 μm and an acetone extraction rate of 65%.

[Production Example 6] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 120 ° C for 1.5 hours. The obtained semi-cured resol resin was roughly crushed with a hammer mill and then finely crushed with a palpelizer. The obtained powdery resol resin semi-cured product (D6) had an average particle size of 150 μm and an acetone extraction rate of 25%.

Examples 1 to 6 Polyethylene and Preparation Example 1
To powdery phenolic resin semi-cured products (D1 to
D6) with the composition shown in Table 1 in a pressure kneader at 190 ° C.,
Melt and knead for 30 minutes. Each of the test pieces was prepared by extruding the obtained phenol resin composition into a sheet.

Comparative Examples 1 and 2 100 parts by weight of polyethylene and the powdery phenolic resin semi-cured products (D1 and D3) obtained in Preparation Examples 1 and 3 were blended as shown in Table 1 with a pressure kneader. Melt and knead at ℃ for 30 minutes. Each of the test pieces was prepared by extruding the obtained phenol resin composition into a sheet.

Comparative Example 3 100 parts by weight of polyethylene was extruded into a sheet to prepare each test piece.

III. Evaluation method of test piece Melt flow index (MFI) is JIS, softening point is JIS, flexural modulus is ASTM D747, combustion test is underwriters laboratories safety standard UL94
(O: burning time within 10 seconds, x: burnt out).

[0030]

[Table 1]

The phenol resin compositions obtained by melt-kneading the polyethylene and the powdery phenolic resin semi-cured products obtained in Examples 1 to 6 had a significantly higher softening point than those obtained in Comparative Examples 1 to 3. The heat resistance is improved and the heat resistance is improved. Further, as a result of the UL-94 combustion test, it is recognized that the flame retardancy is significantly improved.

[0032]

EFFECTS OF THE INVENTION According to the present invention, a phenol resin having flame retardancy, heat resistance, etc., can be used without impairing the excellent characteristics of polyethylene such as moldability, flexibility, and electrical characteristics. You can also add the features you have. For this reason, it can be applied not only in the field where polyethylene has been conventionally used but also in the field where flame retardancy and heat resistance are required.

Claims (4)

[Claims] 1. A phenol resin composition obtained by melt-kneading 100 parts by weight of polyethylene and 5 to 50 parts by weight of a powdery phenol resin semi-cured product. 2. The powdery phenolic resin semi-cured product is obtained by mixing a novolac type phenolic resin and a curing agent and semi-curing the mixture by heating to heat the powdery phenolic resin semi-cured product and / or the resol type phenolic resin. The phenolic resin composition according to claim 1, which is a powdery phenolic resin semi-cured product obtained by semi-curing with an acid. 3. The phenol resin composition according to claim 1, wherein the powdery phenol resin semi-cured product has an acetone extraction rate of 10 to 90%. 4. The phenol resin composition according to claim 1, 2 or 3, wherein the powdery powdered phenol resin semi-cured product has a particle size of 1 to 100 μm.