JPS5836208A - Foamed acrylic fiber - Google Patents

Abstract

PURPOSE:The titled fibers, consisting of an acrylic polymer of a specific composition, having cells consisting of voids, divided by curved surfaces having many fine unevennesses, and having a specific maximal length uniformly in the form of a sponge in the cross section thereof and good flexibility, and useful for handicraft, etc. CONSTITUTION:An acrylic polymer containing at least 40wt% acrylonitrile joined thereto, e.g. acrylonitrile-vinylidene chloride copolymer, is mixed with ethylene carbonate, calcium carbonate and water, etc., and the resultant mixture is molten under heating, extruded while foamed and spun to give the aimed fibers having cells consisting of voids, divided by curved surfaces, and having many fine unevennesses and the maximal length <=150mu uniformly in the form of a sponge in the cross section thereof. Preferably, the bulk density of the fibers is 0.1-0.3g/cm<3>, and the volume fraction of the closed cells based on the total volume of the cells is 10-90%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a foamed fiber made of an acrylic polymer, and an object of the present invention is to provide a foamed fiber useful as a fiber for knitted fabrics, such as a fiber for milling, a fiber for inchwear, etc. do.

Expanded fibers made of acrylic polymers have been known in patents and literature, but K has not yet been widely used as a practical fiber.

So far known acrylic foam fibers include:
U.S. WisIIV Library 3 $42715 No. 111m11 Book 1 It is.

The former is O rice I! The foamed fiber shown here has a polygonal shape surrounded by a thin film and has a honeycomb-like foamed structure consisting of nine closed cells. Konoya Hatsuike Sen 1Ill Hiro,
Although it has excellent bubble size uniformity and foaming degree,
As fibers for woven and knitted fabrics, for example, even if dyed, only the epidermal layer is dyed, and it is difficult to dye with high vertical discoloration.
In addition, it has drawbacks such as low strength and elongation, and poor handling in weaving and knitting processes.

On the other hand, the foamed fiber disclosed in the latter Japanese Patent Application Laid-open No. 54-11172 seems to have a texture and structure similar to natural straw, but it lacks flexibility and is susceptible to sifting due to wear. It may be useful for things like tatami mats, but it is difficult to use as a general-purpose textile fabric.

The present inventors focused on the drawbacks of the conventional foamed fibers mentioned above, and as a result of intensive research, they arrived at the present invention.

That is, the present invention provides at least 4 acrylonitrile
A foamed fiber made of an acrylic polymer having a weight of 0 weight This is an acrylic foam fiber characterized by the fact that the air bubbles are uniformly arranged in a spongy shape.

The acrylic polymer as used in the present invention refers to a polymer containing acrylonitrile alone or acrylonitrile at least 40% by weight, preferably 60% by weight or more, and am consisting of at least one tyrenic unsaturated compound. It is. Here, ethylenically unsaturated compounds include vinyl halides such as vinyl chloride, vinyl bromide, vinyl fluoride, and vinylidene chloride, and vinylidene halide; acrylic acid, methacrylic acid, and! Unsaturated carboxylic acids such as leic acid and itaconic acid and their salts; methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, methoxyethyl acrylate, phenyl acrylate,
O acrylic acid esters such as cyclohexyl acrylate;
Methacrylic acid esters such as butyl methacrylate, octyl methacrylate, methoxyethyl methacrylate, phenyl methacrylate, cyclohexyl methacrylate; Methylvinyl lactones; vinyl acetate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate Etc.Obi! Vinyl ethers such as methyl vinyl ether and vinyl ether; Acrylamide and its alkyl substituted products; Unsaturated sulfonic acids such as vinyl sulfonic acid and p-styrene sulfonic acid and their salts; Styrene, d-methylstyrene, chloro Styrene such as styrene and its alkyl or halogen-substituted products; Allyl alcohol and its esters are ethers; Basic vinyl compounds such as vinylpyridine, vinylidazole, dimethylaminoethyl methacrylate; acrolein, methacrolein, vinylidene cyanide , glycidyl methacrylate, vinyl compounds such as trimethacrylate, and also includes mixtures thereof.

In order to achieve the purpose of the present invention, it is important to have a specific cell structure. That is, as shown in FIGS. 1 and 2, the foamed fibers of the present invention do not have voids separated by curved surfaces having many minute irregularities in the cross section of the foamed fibers, and the maximum length of the voids is Bubbles with a diameter of 150μ or less are uniformly arranged in a cavernous shape.

Figure 1 is a typical scanning lid electron microscope photograph of the cross section of the foamed fiber of the present invention, and Figure 2 is a photograph of the cross section of the fiber obtained by crushing the foamed fiber as shown in Figure 1.

In this case, the film forming the bubbles has a large number of minute irregularities, as clearly shown in FIG. When this film is thin and planar as shown in Figure 3, the bulk density is (L 19101
The fiber has a very high degree of foaming as shown below, but most of the fibers are closed cells, and the surface layer of the fiber has a thin film.
This results in brittle fibers with low strength and elongation, and when dyed, the very surface layer of the tun fiber remains 0@0, and if the fiber surface partially peels off due to friction, the undyed portion is exposed. However, it becomes white and rounded, which is not practical.

Furthermore, the size of the void forming the bubble is the maximum length i
i (largest diameter in one gap) is 150μ
It is necessary that the number of particles is equal to or less than 1, and that they are uniformly arranged. As shown in Fig. 4, foamed fibers that are non-uniform and dotted with coarse bubbles with a maximum length of 150μ or more, especially around several hundred micrometers, have a high bulk density of <0.3 to 0.597.
o! It is difficult to use as a general-purpose weaving and knitting fiber because it has a low degree of foaming, and is therefore rough and rigid, and can become fibrillated, cracked, and cracked due to external forces such as stuttering and abrasion. be.

The method for producing the foamed fiber of the present invention is not particularly limited as long as it is possible to produce the foamed fiber of the present invention;
An example of a suitable manufacturing method will be described below.

100 parts by weight of the above-mentioned acrylic polymer and 5 to 40 parts by weight of water
Parts by weight, 1 to 20 parts by weight of plasticizer and 0.1 to 0.1 parts by weight of inorganic particles
The polymer composition of the present invention can be prepared by heating and melting a polymer composition consisting of 50 parts by weight under autogenous pressure or higher pressure, foaming and extruding it from a spinning orifice, and subjecting it to elongation and heat treatment as necessary. Foamed fibers can be produced.

As the inorganic particles, those that do not dissolve or fall off in the fiber manufacturing process described below and have an average particle diameter of 40 μm or less can be used. Specifically, employee calcium acid, carbonic acid! Gnesium, barium carbonate, kaolin, aluna, Merck,
Titanium oxide, antimony oxide and mixtures thereof can be used.

Although the inorganic particles remain in the resulting foamed fibers, the inclusion of the inorganic particles improves the whiteness of the resulting foamed fibers, which is desirable in the present invention.

On the other hand, as plasticizers, ethylene carbonate, DMF
Asiacrylic polymer agents, triethyl phosphate, etc.
F'') Phosphate esters such as n-'j tyl phosphate, tricresyl phosphate, triphenyl phosphate, halogenated phosphoric acid ester, dioctyl adipate, dimethyl terephthalate, diethyl heptathalate, dibutyl phthalate, dioctyl phthalate, etc. Dibasic acid esters, low molecular weight polyethylene, low molecular weight polypropylene, hydrophobic oligomers such as terpene resins, and mixtures thereof are used.

The foamed fibers of the present invention can be obtained by appropriately selecting these conditions, but in order to achieve the purpose of the present invention, the bulk density and closed cell volume fraction of the foamed fibers to be obtained, as defined later, must be adjusted. It is desirable to adjust it to an appropriate range.

If the bulk density is too low, the strength and elongation of the foamed fibers tends to decrease, and if the bulk density is too high, the foam fibers tend to lose flexibility. In the foamed fiber of the present invention, 0.1
A range of 0.39/Ci to 0.39/Ci is a practically preferable range.

On the other hand, foamed fibers with a high volume fraction of closed cells, in which most of the cells are closed cells, are undesirable because only the outermost layer is dyed under normal dyeing conditions, as mentioned above. In the case of a foamed fiber in which the closed cell volume fraction is low and most of the cells are open cells, it is not possible to maintain the fluffy elasticity characteristic of the foamed fiber. For the foamed fibers of the present invention, a range of 10 to 90X is practically preferable.

Note that the bulk density and closed cell volume fraction described above can be adjusted as appropriate by selecting the manufacturing conditions described above.

Further, as the acrylic polymer, a polymer containing halogen-containing vinyl polymers bound up to 40 weight X is used,
It is particularly desirable to select antimony trioxide as the inorganic particles, blend a phosphate ester plasticizer as necessary, and foam and extrude the composition in order to improve the flammability of the resulting foamed fibers. be.

The amount of antimony trioxide contained in one fiber is preferably 5 to 50 parts by weight based on 100 parts by weight of the polymer portion. If the amount is less than 5 parts by weight, the flame retardant effect will be low, and if it is more than 50 parts by weight, the foamed fibers themselves will become brittle, which is not preferred in practice. The content of the phosphoric acid ester plasticizer is 20% by weight of the polymer. If it exceeds 20 parts by weight, the softening agent will seep out from inside the fibers, which is not desirable for practical purposes.

The acrylic foam fibers obtained in this way have superior physical properties in strength, elongation, and flexibility compared to conventionally known acrylic foam fibers, and are able to fully exhibit the excellent dyeability characteristic of acrylic fibers. It is something.

Therefore, in addition to the above-mentioned properties, the foamed fiber of the present invention has characteristics such as a lightweight feel, excellent heat retention, and excellent water absorption properties due to its uniform and fine foam structure, and is unique in that it has a rich crisp feel. It has a texture and luster, and is useful for a wide range of purposes, including sand, hand-use fiber, wallpaper, rugs, and other indoor fibers, as well as water-absorbent fibers, agricultural materials, and other uses.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited in any way by the description of these Examples.

In addition, the bulk density and closed cell volume fraction in the examples are as follows:
It was measured using the method below.

(1) Take an appropriate amount of sample (length 40 to 50 CIl>o) and measure the weight. Define it as W(9).

Measure the volume of the sample using an air comparison hydrometer (manufactured by Peckman). Let vI(cIr).

(3) After thoroughly immersing the above sample in melted paraffin and taking it out, quickly put it into the basket of the Centre dehydrator (direction 1110e1m) kept at 100-110℃, leave it for 1 minute, and then Decompress and obtain a paraffin-coated sample.

(4) The volume of the above paraffin coated sample is (2)
to flatter in the same way. Let Vt (ej).

俤) Calculate using the following formula.

Bulk degree = WΔ, (g shoulder) Closed cell volume fraction = ((Vl - W%, +7)/(V
t-W/kl? ))×100~ Note that kl and f are the specific gravity of the polymer.

In addition, evaluation of flexibility was performed as follows.

Jun-ge tester (K E 8-F! i Co., Ltd. Kato Iron Works #4) K-yoshi, curvature 1. The bending rigidity at OK was measured, and each numerical value was divided by the smallest numerical value among the obtained round numerical values, and evaluated as a comparative value.

Furthermore, the state of the dyed product was determined using MERED3 (Sumitomo Chemical II) as the dye, dyed at 100°C for 1 hour, and dried for 10 minutes.
Regarding A, observe the cross section and put cellophane tape on the surface.
Evaluation was made by observing the condition of the yarn surface when the yarn was applied and peeled off.

Implementation Ga 1 Acrylonitrile 92% by weight, methyl acrylate 7.5%
100 parts by weight of an acrylic polymer consisting of 0.5 parts by weight of sodium methallylsulfone, 15 parts by weight of water.
The 9 parts by weight of ethylene carbonate, 5 parts by weight of ethylene carbonate, and 5 parts by weight of calcium oxide were fed through a hopper of a single screw extruder having three heating zones, and foaming extrusion was performed. Counting from the hopper side, the first heating zone is 1201::, the second heating zone is 150℃%S
A second heating zone and spinning orifice were installed at 19 Oc. A spinning orifice with one pore with a diameter of 1 m1 was used, and extrusion was carried out at an extrusion pressure of 80 kl/elllk''.The extruded foamed extrudate was wound up for 150 m7 minutes to form a foamed #11 fiber. Obtained.

The first scanning electron micrograph of the cross section of the foamed fibers obtained is
As shown in the figure.

Example 2 A foamed extrudate extruded using the same composition as in Example 1 and under the same equipment conditions was rolled with a nip type roll to form a foam extrudate of 125
It was rolled up in 7 minutes to obtain flat foamed fibers. A scanning electron micrograph of the cross section of the obtained foamed fiber is shown in Figure JIK2.

Implementation yes: 100 parts by weight of an acrylic polymer consisting of 0 parts by weight of acrylonitric acid and 50 parts by weight of vinylidene chloride, 10 parts by weight of antimony trioxide, 2 parts by weight of calcium legate,
A composition containing 2 parts by weight of ethylene carb*-) and 15 parts by weight of water was extruded at a spinning temperature of 170C to obtain foamed fibers with a foam size of 1 m! The cross section of the fiber was similar to that shown in Figure 1, and when the lower end of the fiber held vertically was set on fire with a pine flame, it exhibited self-extinguishing properties.

Comparative Example Using the same polymer as Example 1, U.S.G.A. Patent No. 1s542
Expanded fibers were obtained according to Example 2 of No. 715. The cross-section of the obtained 90-year-old filament is similar to that shown in Figure 5 (referred to as a comparison person).

Using the same polymer, foamed fibers were obtained according to Example 1 of JP-A-54-11172. The cross section of the fiber obtained was similar to that shown in Figure 4 (referred to as Comparison B).

Table 1 shows the physical properties of the fibers of the 111 examples with the above ratios and Examples 1 and 2.

Table 1

[Brief explanation of the drawing]

FIGS. 1 and 2 are scanning electron micrographs of cross-sections of foamed fibers of the present invention, and FIG. 5 is US Patent No. ! 542715
FIG. 4 is a cross-sectional photograph of the foamed fibers described in the % Kaishu No. 54-11172 publication. Figure 1 Figure 2 071A- p5 [Figure PO2 Figure 2 Procedural amendment (method) % formula % Indication of the case Patent application No. 150245/1983 2 Name of the invention Acrylic foam fiber 3 Person making the amendment Relationship with one case・Patent Applicant (OOS) Asahi Kasei Industries Co., Ltd. Agent 5th floor, Toranomon Industrial Building, 2-29 Toranomon-chome, Minato-ku, Tokyo ＼ Details of the amendment ＼ We will submit sg3 drawings and drawings 4 as attached. . Figure 5 Figure 4 Amendment to Figure Proceedings September 30, 1980 Director of the Patent Office Blind Kazuo Wakasugi 1 Indication of the case Patent Application No. 15026iS of 1983 2 Name of the invention Acrylic foamed silver wire 5 Amendment to the sound observation case Relationship between patent applicant (OOG) Asahi Kasei Industries, Ltd. 4 Agent Toranomon Sangyo Pill 5F Toranomon Sangyo Pill, Minato-ku, Tokyo Correct as follows. (11. Correct “this way” on page 2, line 18 to “like this.” (311, page 6, line 15, ``friction'' is corrected to ``friction''. (4), page 7, line 4, ``friction'' is corrected to ``friction.''). (5: , page 8, line 11, "cresyl phosphate" t "talesyl phosphate" is corrected. (61, page 9, line 1, corrected as "After the foamed fibers, Jt-r foamed III fibers, after") In (7), page 11, line 6, "Use for materials" is corrected to "Use for clothing."

Claims (4)

[Claims] (1) A foamed fiber made of an acrylic polymer having at least 40% by weight of acrylonitrile as a binder; Maximum length is 15
An acrylic foam fiber characterized by having air bubbles of 0μ or less uniformly arranged in a spongy shape. (2) Claim II in which the bulk density is 0.1 to 0, s 9Af, and the volume fraction of closed cells to the total cell volume is 10 to 9ON! The foamed fiber according to item II. (3) A patent in which the acrylic polymer contains one unit of a halogen-containing vinyl monomer bonded to up to 40 parts by weight, and also contains 5 to 50 parts by weight of antimony trioxide based on the polymer. The foamed fiber according to claim 1. (4) Claim 8 containing up to 20 parts by weight of phosphoric acid ester per 100 parts by weight of the acrylic polymer
The foamed fiber according to item 3.