JPH0892432A - Phenol resin composition - Google Patents

Abstract

PURPOSE: To obtain a phenol resin compsn. excellent in flame retardancy and mechanical strengths without detriment to the excellent characteristics inherent in polyethylenes by melt mixing a polyethylene with a specified amt. of a cured phenol resin powder. CONSTITUTION: This resin compsn. is prepd. by melt mixing and kneading 100 pts.wt. polyethylene and 5-50 pts.wt. cured phenol resin powder (pref. having an acetone extractable content lower than 10% and a particle size of 1-100μm and comprising, for example, the one prepd. by mixing a novolak phenol resin with a curative and curing the mixture by heating and/or the one prepd. by curing a resole phenol resin by heating or using an acid). Thus, the excellent characteristics, such as flame retardancy and mechanical strenths, inherent in a phenol resin are imparted to the polyethylene without detriment to the excellent characteristics, such as moldability, flexibility, 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 mechanical strength. It is useful for various molded articles obtained by, for example, and applications obtained by extrusion molding.

[0002]

2. Description of the Related Art Polyethylene is used in a wide range of fields because of its excellent electrical properties, mechanical properties and processability, and its 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.

Cross-linked polyethylene having improved mechanical strength and heat resistance is used as a main material for power cables. Although polyethylene itself has excellent electrical properties and chemical stability as a cable material, mechanical strength and heat resistance 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 phenolic resin composition which is excellent in flame retardancy and mechanical strength, with almost no deterioration of excellent characteristics of polyethylene.

The inventors of the present invention have studied the phenol resin for many years, and as a result, have melt-kneaded polyethylene and a powdery phenol resin cured product with the characteristics of the phenol resin such as flame retardancy and mechanical strength. It was possible to obtain a phenol resin composition obtained from the above. As a result of further intensive study, the acetone extraction rate of the powdery phenolic resin cured product is less than 10%, and the particle size of the powder is 1 to 100.
It was found that flame retardancy and mechanical strength are improved by using a powdered phenol resin cured product having a thickness of μm, and the present invention has been completed.

[0006]

The present invention relates to a phenol resin composition obtained by melt-kneading 100 parts by weight of polyethylene and 5 to 50 parts by weight of a powdered phenol resin cured product, preferably 100 parts by weight of polyethylene. And a phenol resin composition obtained by melt-kneading 5 to 30 parts by weight of a powdered phenol resin cured product.

The polyethylene used in the present invention is not particularly limited and is generally commercially available.
Here, when the amount of the powdered phenolic resin cured product is less than 5 parts by weight based on 100 parts by weight of polyethylene, the excellent characteristics of the phenolic resin are not exhibited. Also, 50
If it exceeds the weight part, the moldability of polyethylene and the appearance of the molded product are impaired.

Further, in the present invention, preferably, a phenolic resin cured product having an acetone extraction rate of less than 10% is pulverized and powdered, and the powdered phenolic resin cured product has a particle diameter of 1 to 100 μm. used. Here, if the particle size of the powder is less than 1 μm, the workability at the time of melt-kneading is reduced because it is extremely fine, and if the particle size of the powder exceeds 100 μm, the appearance of the molded product may be impaired. is there.

Examples of the phenol resin used when preparing the powdery phenol resin 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 powdered phenol resin cured product obtained by mixing a novolac type phenol resin and a curing agent and curing by heating and / or a cured product obtained by curing a resol type phenol resin by heating or an acid.

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 reacts phenols (P) and aldehydes (F) at a compounding ratio such that the compounding molar ratio (F / P) is 1.0 to 2.0. Charged in a kettle, and as a catalyst for resinification, hydroxides or oxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, barium hydroxide and calcium hydroxide, amines such as ammonia and triethylamine. In the case of obtaining a modified resin, one or more selected from the above are added, and then a modifying agent is further added, followed by heating and refluxing for an appropriate time, and then removing condensed water generated by the reaction. Therefore, 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 producing the powdery phenolic resin cured product used in the present invention, a method using heat and an acid is typically mentioned, and a curing method using heat is particularly preferable. In case of novolac type phenolic resin,
A novolac type phenolic resin 10 is prepared by adjusting the curing agent such as hexamethylenetetramine to the target degree of the crosslinked structure.
1 to 20 parts by weight is added to 0 parts by weight and mixed to cure.

In the present invention, the degree of curing of the powdery phenolic resin 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, uncured phenolic resin dissolves in acetone,
It does not dissolve as the curing progresses. A completely cured powdery phenol resin cured product does not dissolve in acetone at all. That is, the completely cured phenol resin cured product has an acetone extraction rate of 0%, and the uncured phenol resin has an acetone extraction rate of 100%.

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 cured product having a cured structure with an acetone extraction rate of less than 10% is produced, the heating temperature is preferably 100 to 180 ° C.

A hammer mill, a free mill, a pulverizer, a turbo mill, a jet mill or the like can be used for pulverizing the powdery phenol resin cured product. 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. At this time, the feed rate of the raw material to the crusher, the rotation speed of the crusher, and the particle size obtained depend on the mesh of the screen of the crusher.

[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] 1000 parts of phenol, 1510 parts of 37% aqueous formaldehyde solution and 100 parts of 28% ammonia water were charged in the same reactor as in Synthesis Example 1. 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 Cured Product [Preparation Example 1] 1000 parts of the novolak type phenol resin (B1) synthesized in Synthesis Example 1 and 100 parts of hexamethylenetetramine were mixed and pulverized, and then 60 minutes at 120 ° C and further 60 minutes at 160 ° C. Heated. The semi-cured novolak resin obtained was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The obtained powdery novolac resin cured product (D1) had an average particle size of 40 μm and an acetone extraction rate of 7%.

[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 110 ° C for 2 hours and further at 140 ° C for 90 minutes. The obtained cured novolak resin was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The obtained powdery novolac resin cured product (D2) had an average particle size of 60 μm,
The acetone extraction rate was 9%.

[Production Example 3] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 150 ° C for 1 hour. The obtained resole resin cured product was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The average particle size of the obtained powdery resol resin cured product (D3) is 45.
μm, and the acetone extraction rate was 0.6%.

[Production Example 4] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 130 ° C for 90 minutes. The obtained resol resin cured product was roughly pulverized with a hammer mill and then finely pulverized with a jet mill. The average particle diameter of the obtained powdery resol resin cured product (D4) is 15μ.
m, and the acetone extraction rate was 1.5%.

[Production Example 5] 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 30 minutes and further at 160 ° C for 60 minutes. The obtained novolak resin cured product was roughly pulverized with a hammer mill and then finely pulverized with a pulverizer and a jet mill. The obtained powdery novolac resin cured product (D5) had an average particle size of 0.8 μm and an acetone extraction rate of 9%.

[Production Example 6] The resol-type phenol resin (B2) synthesized in Synthesis Example 2 was heated at 140 ° C for 60 minutes. The obtained resole resin cured product was roughly pulverized with a hammer mill and then finely pulverized with a palpelizer. The average particle diameter of the obtained powdery resol resin cured product (D6) is 15
It was 0 μm, and the acetone extraction rate was 6%.

Examples 1 to 6 Polyethylene and Preparation Example 1
Powdered phenolic resin cured products (D1 to D
6) with the composition shown in Table 1 in a pressure kneader at 190 ° C., 3
Melt and knead for 0 minutes. Each of the test pieces was prepared by extruding the obtained phenol resin composition into a sheet.

Comparative Examples 1-2 Polyethylene and Preparation Example 1
And the powdery phenolic resin cured products (D
1, D3) with the composition shown in Table 1 in a pressure kneader to 190
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, bending rigidity is ASTM D747, and combustion test is underwriters laboratories safety standard UL94.
(O: burning time within 10 seconds, x: burnt out).

[0030]

[Table 1]

Phenolic resin compositions obtained by melt-kneading the polyethylene obtained in Examples 1 to 6 and the powdery phenolic resin cured product were compared with those obtained in Comparative Examples 1 to 3.
Bending rigidity is high, and improvement in mechanical strength is observed. As a result of UL94 combustion test, it was confirmed that the flame retardancy was improved.

[0032]

EFFECTS OF THE INVENTION According to the present invention, a phenol resin having flame retardancy and mechanical strength without impairing the excellent characteristics of polyethylene such as moldability, flexibility, and electrical characteristics. The features of can be added. Therefore, not only in the fields where polyethylene has been used, but also in flame retardance,
It can be applied even in fields requiring mechanical strength.

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 cured product. 2. A powdery phenolic resin cured product is obtained by mixing a novolac type phenolic resin and a curing agent and curing the powdery phenolic resin cured product and / or a resol type phenolic resin by heating or acid. The phenol resin composition according to claim 1, which is a powdered phenol resin cured product obtained by the above. 3. The phenol resin composition according to claim 1, wherein the powdery phenolic resin cured product has an acetone extraction rate of less than 10%. 4. The phenol resin composition according to claim 1, 2 or 3, wherein the powder of the powdered phenol resin cured product has a particle size of 1 to 100 μm.