JPH0694531B2 - A phenol resin composition for felt - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a phenol resin composition for felt used as a binder for fibers during felt production, and particularly to a phenol resin composition for felt excellent in curing speed in an oven. Regarding

[Prior Art] As a phenolic resin composition for a felt to accelerate the curing speed, a novolac type phenolic resin or a mixed resin of a novolac type phenolic resin and a solid resol type resin is blended with an aromatic carboxylic acid. It is known (Japanese Patent Laid-Open No. 58-59253).

[Problems to be Solved by the Invention] In the above-mentioned conventional phenolic resin composition for felt, the aromatic carboxylic acid has a high cost, and if it is compounded until it has an effect on the curing rate, the product cost increases and it cannot be used in terms of cost. .

Further, although the curing rate is improved by blending the aromatic carboxylic acid, the tensile strength and elasticity of the felt after cooling are lowered, so that it is necessary to increase the addition amount of the resin. Benzoic acid,
Aromatic carboxylic acids such as salicylic acid sublime at temperatures below 100 ° C., so it is necessary to increase the blending amount, which increases the product cost and deteriorates the working environment.

The present invention overcomes the above-mentioned drawbacks, and an object of the present invention is to provide a phenolic resin composition for felt, which does not reduce the tensile strength and resilience of the felt and has an improved curing rate at low cost.

[Means for Solving Problems] The felt phenol resin composition of the present invention contains a phenol resin, a curing agent and a curing accelerator, and the curing accelerator is based on 100 parts by weight of the phenol resin. It is characterized in that it comprises 0.1 to 5 parts by weight of an ammonium salt.

Phenolic resin refers to a resin synthesized by subjecting phenols such as phenol, xylenol, cresol and the like and aldehydes such as formalin and paraformaldehyde to a condensation reaction under a predetermined catalyst. Here, an acid, ammonia, or the like can be used as the catalyst. The former is a novolac type phenol resin, and the latter is a resol type phenol resin.

The phenolic resin can be a novolac type phenolic resin or a mixture of a novolac type phenolic resin and a solid resol type phenolic resin. Here, the solid resol-type phenol resin is a resin solidified by subjecting a predetermined raw material to a condensation reaction using ammonia or the like as a catalyst and performing dehydration under reduced pressure. As for the mixture, when both resins constituting the mixture are 100 parts by weight, the novolac type resin can be 30 to 100 parts by weight and the solid resol type resin can be the rest.

If the compounding amount of the ammonium salt of the curing accelerator is less than 0.1 parts by weight, the effect is not obtained, and if it exceeds 5 parts by weight, the effect is saturated. The ammonium salt may be an ammonium salt of various strong acids or weak acids, for example, one of ammonium chloride, ammonium nitrate, ammonium sulfate and ammonium phosphate.

The ammonium salt may be mixed into the resin at the time of synthesizing the resin, or may be mixed with the resin, the curing agent and the lubricant at the time of pulverization and mixed and pulverized.

Various additives such as a lubricant such as stearic acid and a curing agent such as hexamethylenetetramine can be added to the resin composition.

[Operation] When the composition is used as a binder for felt,
Usually, phenol resin such as novolac type phenol resin is mixed with hexamethylenetetramine as a curing agent in an amount of 3 to 15 pHR. It is considered that the ammonium salt is thermally decomposed when heated in an oven to generate an acid, which accelerates the decomposition of hexamethylenetetramine and accelerates the curing of the phenol resin.

Further, it is considered that the ammonia generated by the decomposition acts as a cross-linking agent for the novolac resin and is effective in improving the curing rate.

[Effects of the Invention] The felt phenol resin composition of the present invention comprises a phenol resin mixed with 0.1 to 5 parts by weight of an ammonium salt per 100 parts by weight of the phenol resin.

Therefore, when the present composition is applied to the felt resin, the curing speed of the felt resin is increased, so that the energy cost can be reduced by lowering the oven temperature during the felt manufacturing, and the productivity can be improved by shortening the oven passage time. Also, maintenance costs can be reduced by reducing the number of cleanings due to the reduction of dirt on the steel belt in the oven.

Further, in the conventional composition, the phenol resin mixed and blended with the fleece does not supply the heat necessary for sufficient curing, so that 5 to 15% of uncured felt resin is present in the felt. On the other hand, when the composition of the present invention is used, the unreacted resin can be reduced by accelerating the curing of the felt resin, and the addition amount of this resin can be reduced.

[Examples] Hereinafter, the present invention will be described with reference to Examples.

Example 1 100 parts by weight of a normal novolac type phenolic resin (hereinafter simply referred to as "part"), 12 parts of hexamethylenetetramine, 1 part of calcium stearate and 0.5 part of ammonium nitrate were mixed and pulverized with a mixer to prepare a felt resin composition.
Using this resin composition for felt, the flow, gel time, stiffness and strength were measured. The results are shown in the table.

The evaluation of this flow and gel time was performed according to JIS K-6910. Evaluation of tensile strength or stiffness was performed as follows. That is, first, (1) 200 g of raw cotton, the above composition
40 g was blended and mixed by a crusher, and this was hot pressed at 200 ° C. for 5 minutes to be cured. The test piece size is 50 ×
It is 200 mm. Tensile strength of this test piece was measured with Tensilon (STM-F-500 manufactured by Toyo Baldon).
The measurement was performed at 20 mm / min. Koshi (bend) placed a test piece on a beam with a fulcrum distance of 10 cm, placed a weight of 100 g in the center, and measured the amount of deflection after 10 seconds using a dial gauge.

Example 2 80 parts of normal novolac type phenolic resin A felt resin composition was prepared in the same manner as in Example 1 using 20 parts of a usual solid resol type phenol resin, 5 parts of hexamethylenetetramine, 1 part of calcium stearate and 0.5 part of ammonium chloride, and the same test was conducted. The results are shown in the table.

Comparative Example A felt resin composition was prepared in the same manner as in Example 1 using 100 parts of a normal novolac type phenolic resin, 12 parts of hexamethylenetetramine, 1 part of calcium stearate and 2 parts of salicylic acid, and the same test was conducted. Is shown in the table.

According to the results of this table, in Examples 1 and 2, the tensile strength and the stiffness are improved, the flow is good, the gel time is shortened, and the curing rate is improved, as compared with the comparative example.

Claims (3)

[Claims] 1. A powdery form containing a phenol resin, a curing agent and a curing accelerator, wherein the curing accelerator comprises an ammonium salt in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the phenol resin. A phenolic resin composition for felt, which is characterized in that: 2. The felt phenolic resin composition according to claim 1, wherein the phenolic resin is a novolac type phenolic resin or a mixture of a novolac type phenolic resin and a solid resoleuric type phenolic resin. 3. The phenolic resin composition for felt according to claim 1, wherein the ammonium salt of the curing accelerator is one of ammonium chloride, ammonium nitrate and ammonium sulfate.