JPS5843520B2 - Glass sensor icon - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing glass fiber mixed paper, and more specifically, a method for manufacturing glass fiber mixed paper that has glass fibers uniformly dispersed and has extremely high dimensional stability. It is related to.

It is known to incorporate glass fibers into pulp for the purpose of improving the dimensional stability of paper.

If a generally commercially available chopped strand of glass fiber for FRP is used to manufacture such a mixed paper, there will be some problems in terms of the mixing operation and the quality of the product.

In other words, chopped strands of glass fiber for FRP are
During the spinning process, a spinning aid is applied, and therefore, the 0
, approximately 5% of organic matter is attached to the fiber surface.

The first problem caused by such surface deposits is
When chopped strands of glass fiber are put into water or pulp solution and stirred to dissociate them into single fibers, the dissociation of the fiber bundle is poor and the dispersion operation takes a long time, or undissociated fibers This means that some bundles remain.

The second problem is that since the deposits on the glass fiber surface are hydrophobic, the glass fibers tend to aggregate together in water, resulting in poor dispersion of the glass fibers in the resulting mixed paper. In other words, loose bundled fibers are distributed in a network pattern.

For this reason, the resulting mixed paper not only has poor dimensional stability but also poor paper surface smoothness, which may cause problems in use and performance depending on the application.

The purpose of the present invention is to solve the problems of the conventional methods as described above, improve the dispersibility of glass fibers in the papermaking liquid, and provide a method for manufacturing glass fiber-mixed paper with excellent dimensional stability and smoothness. It is about providing.

The above object is achieved by the method of the present invention, which comprises mixing 70-95% by weight of pulp with 5-30% by weight of glass fibers treated with a spinning aid to produce glass-mixed paper. At this time, the glass fiber is heated to a temperature of 400°C or higher and lower than its melting point to incinerate the surface deposits, and then is rapidly brought into contact with cooling water to be rapidly cooled. It is something.

As mentioned above, in the fiber manufacturing process, a solution of vinyl acetate or starch is applied to glass fibers as a sizing agent, and a solution of borane or a silane compound is applied as a coupling agent. In the method, when the glass fibers are heated to a temperature above 400°C and below the melting point of the glass fibers, these spinning aids are thermally decomposed;
V will be completely incinerated within 30 minutes.

If this heating temperature is lower than 400°C, it is difficult to completely incinerate the spinning aid within a practical time.

Moreover, since the glass fibers will melt when the heating temperature is higher than the melting point of the glass fibers, such temperatures naturally cannot be used.

In particular, if the spinning aid is not completely burnt out, the hydrophobicity of the fiber surface may be increased, which may inhibit the dissociation and dispersion of the glass fibers in the papermaking liquid.

In the method of the present invention, a conventional heating device such as an electric furnace, an infrared heating device, a hot air heating furnace, etc. can be used for the heating step of the glass fiber.

The glass fibers are fed in the form of chopped strands into the heating device either continuously or batchwise.

This heat treatment significantly improves the dispersibility of the glass fibers in water, and by slow or short stirring, the glass fibers can be uniformly dispersed in the form of single fibers in water.

Therefore, the glass single fibers are less likely to break due to the stirring operation, and therefore the length of the glass fibers can be maintained.

In addition, mixed paper made with heat-treated glass fibers,
It has significantly improved dimensional stability compared to mixed yarn using glass fiber that is not heat treated.

Although the reason for this improvement is not clear, it is believed that the surface of the heat-treated glass fiber has improved adhesion to the pulp fiber.

In the method of the present invention, the high temperature heat treated glass fibers are then brought into rapid contact with cooling water and quenched.

This contact with the cooling water may be achieved by putting the glass fibers into the cooling water, by spraying the glass fibers with cooling water, or by spraying the glass fibers with cooling water.
Alternatively, the glass fibers may be run continuously through the cooling water stream.

Generally, when glass fibers that have been heat-treated at high temperatures are brought into sudden contact with cooling water, it is expected that the glass fibers will shatter into powder due to the sudden and uneven contraction, but the reality is contrary to this prediction. It was confirmed that no cutting or crushing of glass fibers occurred.

In fact, mixed paper made with quenched glass fibers is better than mixed paper made with glass fibers slowly cooled in air.
The surprising effect of high dimensional stability was observed.

Although the reason for this is not clear, it is thought that the Young's modulus of the glass fiber is improved by the quenching effect of heating and quenching.

Furthermore, the rapid cooling method of the present invention has the following advantages.

(4) Cooling equipment is simple and cooling time is short.

If slow cooling is to be performed, a large slow cooling chamber is required to accommodate a large amount of glass fibers.

(B) The heat possessed by high-temperature-treated glass fibers is recovered by cooling water, and this amount of heat is effectively used to raise the white water temperature in the papermaking process, thereby increasing the degree of fiber dispersion and shortening drying time. be able to.

However, in the slow cooling method, the heat possessed by the glass fibers is released into the atmosphere and is difficult to recover.

As described above, in the method of the present invention, by combining high-temperature heating treatment and rapid cooling treatment, the dissociation and dispersion treatment of glass fibers in the papermaking liquid is facilitated, and a mixed paper with high dimensional stability can be produced. I can do it.

Furthermore, the mixed paper produced by the method of the present invention has glass fibers uniformly dispersed in the form of single fibers, no undissociated fiber bundles, and excellent surface smoothness.

Furthermore, the method of the present invention simplifies the cooling device and facilitates the recovery of heat.

The structure and effects of the method of the present invention will be explained below with reference to Examples.

Example Chopped strand (product name: C8-06HA-83O) with a length of 6 mm and a thickness of 9 μ manufactured by Asahi Fiberglass Co., Ltd.
22 males of A) were weighed.

This glass fiber is hereinafter referred to as glass fiber I.

Separately, 22 g of the same glass fiber as above was taken, placed in a crucible, and heat-treated at 450° C. for 30 minutes in an electric furnace.

This glass fiber was taken out of the electric furnace and placed in the air for about 1
It was left to cool for an hour.

The obtained fiber is hereinafter referred to as glass fiber (■).

Further, the same glass fiber 221 as above was taken and treated at high temperature in the same manner as above, and then immediately soaked in about 500 r of water at 20'C.
It was put into IL1 and rapidly cooled.

The obtained fiber is hereinafter referred to as glass fiber (■).

Separately, hardwood bleached kraft pulp (hereinafter abbreviated as LBKP) was processed using a beater to produce its Canadian standard pulp.
Beaten to a freeness of 450ml, 1% by weight
Water was added to dilute the pulp solution to a concentrated pulp solution.

This pulp liquid 17.81 (-t-, that is, bone dry pulp 1
(containing 781) was taken, and the glass fiber (2) was put into it while stirring with a reciprocating stirrer.

While stirring, a small amount of the dispersion was taken and the state of dissociation and dispersion was observed on a blue glass. The time required until no bundled fibers were observed was measured, and it was approximately 12 minutes. Ta.

Separately, the dissociation time of the glass fiber L was measured in the same manner as above, and the dissociation time of the glass fiber L was 1 second, but that of the glass fiber L was about 30 seconds.

Made in this way (glass fiber 11%, LBKP8
9%) From three types of materials, the basis weight xoo? /lri' sheets (glass fiber mixed paper I, ■, ■) were made.

After squeezing the wet sheet with a press, it was inserted into a ferrotype with a surface temperature of 105° C. and dried.

The table below shows the results of measuring the underwater elongation and average fiber length of these three types of sheets and a separate sheet (comparison paper) made only from LBKP.

Underwater elongation is the elongation (%) of paper when it is immersed in water at room temperature for a certain period of time, and a Fenchel type underwater elongation measurement device was installed.

The average fiber length was determined by melting the cellulose fibers in a piece of paper with concentrated sulfuric acid to leave glass fibers, which were spread out on a slide glass and exposed to a projector, and the lengths of all the fibers were measured and arithmetic averaged.

From the above table, it can be seen that the glass fiber mixed paper (2) produced by the method of the present invention has the highest dimensional stability in water and also has a large average fiber length of the glass fibers.

Claims (1)

[Claims] When mixing 170-95% by weight of pulp and 5-30% by weight of glass fibers treated with a spinning aid, the glass fibers are heated to a temperature of 400°C or higher and below their melting point. A method for producing glass fiber mixed paper, which is characterized by performing a pretreatment of incinerating the surface deposits, and then rapidly cooling the paper by bringing it into contact with cooling water.