JPS62133163A - Silicone fiber nonwoven fabric and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a silicone fiber nonwoven fabric used for clothing materials, medical hygiene materials, etc. that require elasticity, and a method for producing the same.

(Prior art) Polyurethane elastic fiber nonwoven fabrics have been known as nonwoven fabrics made of elastic fibers.
It is disclosed in Japanese Patent No. 9-223347. This polyurethane elastic fiber nonwoven fabric has excellent elasticity, flexibility, and breathability, so it can be used as interlining, batting, clothing materials such as sportswear, and sanitary materials such as masks, bandages, and wound dressings.
Being frugal. However, polyurethane elastic fiber non-woven fabrics lack heat compatibility, so they cannot be used in applications that require heat treatment, such as ironing, pressing, and steam treatment in the clothing field, and autoclave sterilization in the rainforest field. It also had the disadvantage of being inferior to other materials and prone to discoloration.

On the other hand, silicone rubber is a material that has moderate elasticity and excellent heat resistance and weather resistance, but silicone rubber cannot be made into fibers by existing spinning methods such as melt spinning, dry spinning using a solvent solution, and wet spinning. The nonwoven fabric was also not obtained.

(Objective of the Invention) The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional techniques, and an object of the present invention is to provide a nonwoven fabric made of silicone fibers that has stretchability, heat resistance, and weather resistance.

(Structure of the Invention) The present invention is a silicone fiber nonwoven fabric characterized in that silicone fibers are self-attached at their intersections.

In the silicone fiber nonwoven fabric of the present invention, the silicone fibers form a three-dimensional network structure by self-adhering at fiber intersection points without using other bonding means such as resin bonding 4] or adhesive fibers. Not only is it stretchable and breathable, but it also has the heat resistance, weather resistance, and non-toxic properties that silicone originally has, without any loss when it is made into a nonwoven fabric. Furthermore, the silicone fiber nonwoven fabric of the present invention has an average fiber diameter of 1
Since it is composed of fibers of 00 μm or less, preferably 10 to 60 μm, it is possible to obtain a 4-te green cloth with a soft and flexible feel.

Liquid silicone rubber is used for the silicone m-fiber. Here, liquid silicone rubber is a soft paste or fluid before a hardening reaction, and becomes a rubbery body after hardening, and is a so-called millable type that is a semi-solid plastic before hardening. Silicone rubber is distinguished. Usually, room temperature vulcanization type (RTV) silicone rubber, low temperature vulcanization type (L i'V) silicone rubber, liquid tA4
Silicone rubber for A4 size (IM) belongs to this liquid silicone rubber category. Due to its curing reaction mechanism, this liquid silicone rubber is composed of 5i-0) (silanol having a bond, alkoxysilane, acetoxysilane,
A condensation reaction type in which a silicon compound containing a hydrolyzable group such as oxime silane is reacted with water under a catalyst such as a tin compound, and a polysiloxane having an unsaturated bond such as a vinyl group or an allyl group and a 5i-H bond. There are two types: an addition reaction type in which a polysiloxane is reacted with a platinum medium, and an ultraviolet curing type in which a radical reaction is carried out using ultraviolet light. Of these, the UV-curable VIJ cone rubber is
Condensation reaction type silicone rubber has a slow curing speed and is difficult to form into fibers because by-products are produced by the curing reaction. Therefore, the liquid silicone rubber used in the present invention is particularly preferably an addition reaction type silicone rubber that can be cured in a short time by heating and does not produce by-products during the curing reaction. In addition, the liquid silicone rubber may contain reinforcing fillers such as fumed silica, precipitated silica, diatomaceous earth, and quartz powder, heat resistance improvers such as metal oxides, metal organic hydrochloric acids, platinum, oxidized It may also contain a property improver such as a flame retardant imparting agent such as titanium or carbon black.

Although the silicone fiber nonwoven fabric 1 of the present invention can be used alone, it may be combined with other materials to form a composite when particularly strong strength is required or when a pond function is desired. ! , materials, non-woven fabrics, felts, fiber webs, rubber sheets, films, papers, etc.

Next, the method for producing a silicone fiber nonwoven fabric of the present invention includes a step of discharging liquid silicone that is cured by an addition reaction from the pores, a step of thinning the discharged liquid silicone with an air current to form fibers, and a step of discharging liquid silicone that is cured by an addition reaction into fibers. This process consists of a step of collecting the silicone while it has adhesive properties and forming it into a sheet, and a step of curing the liquid silicone by heating.

Here, the liquid silicone refers to the aforementioned 71c liquid silicone rubber that has not yet been cured or is in the process of being cured but has not yet completely cured.

In addition, liquid silicone that is cured by an addition reaction is composed of polysiloxane having unsaturated bonds such as vinyl groups and allyl groups, polysiloxane having 8i-H bonds, and a platinum catalyst. Silica is a filler for m-A which contains a property improver of Shichinoike. Examples of the above-mentioned polysiloxanes having unsaturated bonds include those represented by the following formula (wherein, R1-Ra is a lower alkyl group, phenyl group, or vinyl group, and n r'110 to 4000). In addition, polysiloxanes having 8 i-H bonds include
For example, there are those expressed by the following formula (where R)
~R13rt is a lower alkyl group or a phenyl group, X, Yri is an integer of 1 or more, and has a total value sufficient to produce a liquid having a viscosity of 10 to 10,000 voids at 25'C. be. ) In order to obtain a silicone rubber with optimal cross-linking efficiency and excellent physical properties, the above ratio of vinyl groups to 8i-H bonds in the liquid silicone should be 0.8:1-1.2:
Particularly preferred are those in the range of 1.

The liquid V recone described above has a viscosity adjusted to KpA in the range of 50 to 10,000 poise, and is discharged from a pore such as a nozzle with a diameter Q of 1 Nllff using a gear pump, a plunger pump, or the like.

The discharged liquid silicone is thinned into fibers by the east flow blown out from around the nozzle. The diameter of the resulting silicone rubber is adjusted by adjusting the airflow velocity, silicone viscosity, pore diameter table, etc., so as not to lose the flower-like texture and function.
Average fiber diameter is 100μ or less, preferably 10 to 60μ
m range. In addition, the temperature of the airflow is 200~5
A heated air stream at 00° C. may be used, in which case the liquid silicone will be hardened.

Heated airflow is particularly effective when the viscosity of liquid silicone is low or when trying to obtain a thick nonwoven fabric, where there is a risk that the silicone fiber shape may collapse and form a film on the collection surface. . However, in such a case,
In order to completely cure the liquid silicone, heated airflow must be applied under conditions that leave it self-adhesive, otherwise the fibers will lose their bonding means and fail! I
become unable to form. In addition to the above, as a means to advance the curing of the liquid silicone halfway and maintain the fiber shape [F], the entire or part of the thread from discharge to collection of fibers may be heated to 1" atr of 50 to 300°C. There are ways to create surrounding energy.

Next, the silicone rubber is collected into a sheet that still has self-adhesive properties. Here, the term "still self-adhesive" refers to a state in which the collected silicone fibers have the property of adhering or adhering to each other at seven contact points. Therefore, the bond between the collected and sheeted Noricone fibers 9 is mainly composed of the fiber contact layer of the silicone fibers. When collecting the silicone fibers, since the silicone fibers have a certain amount of moisture, a material that has mold releasability with respect to silicone is selected for the collection surface. In particular, a material that has heat resistance as well as collection is required, and for example, a belt made of glass fiber fabric whose surface has been treated with fluororesin is used. However, when manufacturing a composite of silicone fiber nonwoven fabric and Ike material, the silicone fibers are collected directly on the Ike material, and the self-maturity of the silicone fibers is utilized to create a composite material for both. In this case, it is better not to have the above-mentioned mold releasability with respect to silicone, since the collection material becomes a bonding material.

9i is used as a means for curing liquid silicone by heating.
In addition to the means using heated air flow described above and the means for heating the collection surface, there are methods for heating the collection surface with a dryer or the like after collection. The method of using heated air current or heated atmosphere as described in this song is effective as a preliminary curing method when the viscosity of liquid silicone is low, but this heating method alone is not effective.
It is difficult to complete the bonding of the fibers after collecting the silicone fibers, so it is better to use a heating method in combination with a pond heating method.Also, heating with a drying machine etc. after collecting the silicone fibers completely completes the bonding of the fibers. However, unless liquid silicone with a very high viscosity is used, the fiber shape will collapse when using this heating method alone, so it is better to combine it with a preliminary heating method. good. On the other hand, it is possible to form a nonwoven fabric by heating the collection surface alone, but if you want to obtain a thick nonwoven fabric, the heat applied to the upper part tends to be insufficient, and the fiber shape Since it is easy to collapse and form a film, it is more preferable to combine it with a preliminary heating means.

Therefore, as a means for curing liquid silicone by heating, a means for heating the collection surface is used.

It is desirable to use a combination of means that uses a heated air stream or heated atmosphere and a means that heats the collection surface, or a combination of a means that uses a heated air stream or heated atmosphere and a means that heats the collection surface after collection. It is particularly effective when obtaining a body.

Note that the temperature for heating is appropriately set depending on the composition of the liquid silicone used and the heating means selected.

(Example) Example 1 Liquid silicone with a viscosity of 1,600 poise was prepared from two-form LIM silicone (KE-1915 manufactured by Shin-Etsu Chemical Co., Ltd.) that hardens through an addition reaction, and this was pumped into a plunger type pump. The discharge pressure is 50Kp.
It was discharged from a nozzle with a diameter of 0.50 at Δ. Next, the discharged liquid silicone is atomized by an air stream blown out from slits provided on both sides of the nozzle, and the liquid silicone is atomized by approximately 350'.
The samples were randomly collected on the heated collection surface. In addition, the collection material is glass fiber coated with fluororesin on the surface! l
I: A belt made of NX material was used.

The obtained silicone fiber non-woven fabric was made of silicone fibers with an average fiber diameter of 60 μm, and had a basis weight of 12011/nf and a thickness of 0.400.

The stretchability, heat resistance, and weather resistance of this nonwoven fabric were tested and evaluated by the following methods. First, the 40% repeated elongation recovery rate was determined for the elasticity.
The nonwoven fabric of this example was elongated by 40% at 1n and immediately recovered to its original length at the same speed 20 times to determine the residual elongation rate l (%). Showed feline nature. Next, the heat resistance of the sample was 1800×10
After standing for 0 hours, the rate of change in tensile strength and elongation before and after heating was examined.

As a result, the tensile strength was -15% and the elongation was -18%, which was small, and compared to nonwoven fabrics made of elastic fibers such as polyurethane m-fiber nonwoven fabrics that cannot maintain their original shape under these conditions. It has been shown to have high heat resistance. Furthermore, the weather resistance was tested using a fetometer tester (manufactured by Suga Test Instruments @) under the conditions of a temperature of 63°C and an ultraviolet irradiation time of 100 hours, and no discoloration or fading was observed, indicating good weather resistance. Ta. In addition, the non-woven Ihd silicone 100 of this example
% and has no toxicity to the human body.

Example 2 Silicone 70 for LIM similar to Example 1
Two-component RTV silicone (
KE-106 manufactured by Shin-Etsu Chemical Co., Ltd.) 30 parts (approx. 5
A liquid silicone having a viscosity of about 300 poise was prepared by mixing the silicone with 0 voids), which was pumped with a plunger type pump and discharged from a nozzle with a diameter of 0.33 fins at a discharge pressure of 50 kg/i.

Next, the discharged liquid silicone was atomized by a stream of air at a temperature of 400°C blown out from an outlet provided around the nozzle, and collected on a collecting surface heated to 3000°C. The same collection material as in Example 1 was used.

According to this method, even if low-viscosity liquid silicone is used, it is possible to make a nonwoven fabric without destroying the fiber shape, so it is possible to produce a nonwoven fabric made of thin fibers.

The obtained non-woven fabric was made of silicone fibers with an average fiber diameter of 30 μm, and had a basis weight of 801/d and a thickness of 0.26 ff.

In addition, the same tests as in Example 1 were conducted for elasticity, heat resistance, and weather resistance, and the elasticity was 40% repeated elongation recovery rate was 86%, and the heat resistance was determined by the rate of change in tensile strength of 121%.
% and elongation change rate was 124%, which was a good value, and no discoloration or fading was observed in weather resistance.

Example 3 The same liquid silicone as in Example 1 was pumped with a plunger type pump and discharged from a nozzle with a diameter of 0.5n at a discharge pressure of 50 Kp/cd.

Next, the discharged liquid silicone was blown out from the outlet provided around the nozzle and atomized with an air flow at 350°C, and collected on a nylon tricot with a fabric weight of 3511/d.After this, it was dried in a dryer. Curing was completed by heating at 150°C for 3 minutes to obtain a composite of silicone fiber nonwoven fabric and nylon tricot.

This method is a convenient and convenient method for producing composites with silicone fiber nonwoven fabric, especially when high temperatures are applied to the collection surface. There is no need to worry about the material shrinking or deforming due to heat.

In the case of this iMl, if the material to be used in multiple units has a certain degree of heat resistance, it is possible to heat it in a Jid enclosure where the material will not be deformed by heat during collection without using a dryer after being collected. It goes without saying.

(Effects of the Invention) The silicone fiber nonwoven fabric of the present invention has a three-dimensional structure in which one silicone #A female shields at its intersection, so it forms a nonwoven fabric made only of silicone as a raw material. be able to. Therefore, the silicone fiber nonwoven fabric of the present invention has excellent not only elasticity but also heat resistance, weather resistance, non-toxicity, etc.
It is particularly suitable for applications that require soft fabric materials, such as those that require heat treatment or those that are used in direct contact with the skin.

The advantage of the present invention's method for manufacturing silicone fiber nonwoven fabrics is that the liquid silicone, which immediately hardens through an addition reaction, is liquid at around room temperature and can be discharged from pores or atomized by air currents.

It was invented after discovering that silicone can be cured in a short time by heating and that silicone particles are self-adhesive to each other before curing. This makes it possible to manufacture with high productivity using simple means.

Claims (1)

[Claims] 1. A silicone fiber nonwoven fabric characterized in that silicone fibers are self-attached at their intersections. 2. The silicone fiber nonwoven fabric according to claim 1, wherein the silicone fibers are formed from liquid silicone rubber that is cured by an addition reaction. 3. A process of discharging liquid silicone that hardens by an addition reaction from the pores, a process of atomizing the discharged liquid silicone with an air current to form fibers, and collecting the fibers while they still have self-adhesive properties to form a sheet. A method for producing a silicone fiber nonwoven fabric comprising the steps of: curing the liquid silicone by heating.