KR810001863B1 - Method of preparing rush-like structure - Google Patents

Abstract

Synthetic rush-like structure showing superior sensefeeling and utility similar to natural rush was manufd. A monomer mixt. consisted of acrylonitrile and/or ethylenically unsatd. compd. was polymd. at >120≰C under the steam pressure in autoclave which comprising 3-50wt.% H2O (on the basis of monomer and water) to give molten acrylonitrile polymer. The molten polymer was extruded to manuf. foam product, which was heat-treated to give rush-like structure.

Description

Method of manufacturing a wedge-shaped structure

The present invention relates to a method for producing a pulpal structure. More specifically, the present invention polymerizes a monomer mixture containing acrylonitrile (hereinafter referred to as AN) alone or AN at high temperature and pressure in the presence of a small amount of water, or composed of AN alone or containing AN Preparing the AN polymer composition in a substantially molten state by heat melting the mixture and water or the mixture with the plasticizer; Dropping the polymer composition in a molten state toward a spinneret; Adjusting the pressure on the system in which the melt exists immediately before the hole to a specific range and extruding the melt to form a foamy product; Heat-treating the foam product thus obtained to obtain a synthetic pulpit structure similar in appearance to the natural pulps and having excellent sensibility and practicality; It relates to a process consisting of.

In Japan, tatami mats, matting mats, and sculptural stones, which are headed by Jnncus, have long been used, but their production has been gradually decreasing in recent years. The reason for this is that on the one hand, it is becoming more difficult to grow high-quality vines as a result of the development of air pollution as the surrounding areas of natural vines are gradually transformed into industrialized areas. On the other hand, cultivation of the vines requires much labor. Therefore, sufficient labor is difficult to secure.

Under such conditions, attempts have been made to actively produce alternatives to natural bone products from synthetic plastics produced on a large scale industrially and stable in quality. For example, a mat in which polyfuropropylene, polyethylene, polyvinyl chloride, and the like is braided into a hollow linear product or a foam linear product is started or sold. In particular, synthetic pulp of polypurofylene has been rapidly spread due to its low price, strength and beautiful appearance. For reference, examples of conventional techniques for producing synthetic husks from synthetic plastics include Japanese Patent Publication No. 3477/1970 (polyethylene foam), Japanese Patent Publication No. 4033/1975 (polyfuropropylene-polyvinyl alcohol product), Japan Utility Model Publication No. 27341/1970 (product of polyolefin) and Japanese Patent Publication No. 23905/1972 (product of polyvinyl alcohol foam and polyvinyl chloride foam).

Synthetic plastics of polypropylene, polyethylene, polyvinyl chloride, or polyvinyl alcohol-based have the advantages of low price and mass production, but the appearance and practicality of natural plastics have not been supplied yet. As such, synthetic hulls cannot exhibit the benefits of natural hulls such as hygroscopicity (absorbency), elastic recovery, dimensional stability and fresh feel, and thus still do not surpass natural hulls in their usefulness.

On the other hand, the tatami surface and the like composed of natural husk does not completely exclude the functional defects, and actually has unsolved problems in practical use. In other words, users are still convinced that there are still insufficient points in light resistance, dyeing, quality uniformity and wear resistance.

When the inventor considers the prior art, tatami which is indispensable to Japanese life still has various problems, and various problems to be improved in the use of tatami made of natural or synthetic husks remain unresolved. Realized.

At this point, the present inventors conducted a study to improve the defects associated with the conventional product, and as a result, the synthetic oyster-like structure made of a special process and composed of an acrylic polymer, and formed of a foamy structure of natural pulps, has all the defects of the conventional product. It has been found that can be removed and thus advantageously used for tatami surfaces.

It is an object of the present invention to provide a technical means for producing a new synthetic hull-like structure.

Another object of the present invention has a moderate elastic recovery and fresh texture, and excellent in light stability, dyeing, quality uniformity, abrasion resistance, absorption ability, hygroscopicity, etc., which can be advantageously used for tatami surfaces, mats, scorpions, etc. It is to provide a method for producing a wedge-like structure.

Other objects of the present invention will become apparent from the following detailed description of the invention.

The object of the present invention is to provide a monomer mixture composed of AN alone or AN and at least one ethylenically unsaturated compound at a pressure above the vapor pressure generated in the polymerization system under polymerization conditions in a system in which water is present in an amount of 3 to 50% by weight. Or a mixture consisting of 40 to 90% by weight of an AN polymer (AN alone or consisting of at least 40% of AN and at least one type of ethylenically unsaturated compound) and 60 to 10% by weight of water (this mixture Is hereinafter referred to as Mixture A), or a mixture of 40 to 90% by weight of the acrylic polymer with 60 to 10% by weight of water (this mixture is hereinafter referred to as Mixture B) and then To the total amount of the polymer and water was added up to 60% by weight of a plasticizer (the former melt from mixture A was converted to polymer melt B and the latter melt from mixture B Polymer melt C), which is prepared in a substantially molten AN polymer composition; The melt thus obtained flows down toward the spinneret; Adjusting the pressure of the system in which the melt is present immediately before the spinneret to 0.5-20 kg / cm ² ; Extrusion of the melt to form a foamy product; It is achieved by heat treatment of the foamed product thus obtained.

Synthetic bone hull-like structure produced by using the above manufacturing process is formed by the surface layer is corrugated in the longitudinal direction, the inner layer has a unique foam-like structure similar to the natural husk having a foam structure. Therefore, this synthetic husk has a fresh texture and luster similar to the tatami made of natural hull. In addition, because of the high wettability of the acrylic polymers used (as a result of the high affinity of the nitrile groups in the AN polymers for water), the pulps have adequate absorption and hygroscopicity. It also has excellent elasticity recovery and dimensional stability, and also has improved quality uniformity and gloss.

Because of the composition of the materials used (acrylic polymers), the artificial hulls according to the invention have a markedly improved light stability and dyeability, which further increases their commercial value.

In addition to being light in weight and easy to handle, the synthetic hull-like structure of the present invention has the advantage of being easily braided by a conventional tatami surface braiding machine.

By using the preparation of special polymer melt A or polymer melt B or polymer melt C, extrusion of the melt under a predetermined controlled pressure to form a foamed product, and heat treatment operation of the obtained foamed product as a synthetic plastic, There has been a successful manufacture of the synthetic pulp-like product of the present invention, which has been endowed with various textures and practical performances that could not be found in the conventional artificial pulp that was constructed, and which does not even have a natural pulp. This is considered to be very important from an industrial and social point of view.

Melting phenomena of the AN polymer (polymer melt A) prepared under the above special conditions of pressure and heat cannot be explained clearly, but the cohesive force due to the interaction between the -C = N groups of the AN polymer molecular chain is It is presumed that the co-action between the unreacted monomers remaining in the polymer product is markedly weakened and consequently the resulting polymer can readily melt.

Preferred embodiments of the present invention are as follows.

-메틸스티렌, 클로로스티렌 등과 같은 스티렌과 그의 알킬- 또는 할로겐-치환체 알릴알콜과 그의 에스텔과 에텔; 비닐피리딘, 비닐이미다졸, 디메틸 아미노에틸 메타크릴레이트 등과 같은 염기성 비닐 화합물; 아크롤레인, 메타크롤레인, 비닐리덴 시아나이드, 글리시딜 메타크릴레이트, 메타 크릴토니트릴 등과 같은 비닐 화합물 등이 포함된다.The pressurized homogeneous polymerization reaction used in the preparation of the synthetic chalcoidal structure is used for the polymerization of the monomer mixture containing AN alone or at least 40% by weight, preferably at least 60% by weight, of AN and at least one ethylenically unsaturated compound. The ethylenically unsaturated compounds which are copolymerization components include known unsaturated compounds that can be copolymerized with AN, such as vinyl halides and vinylidene halides such as vinyl chloride, vinyl embrittlement, vinyl fluoride and vinylidene chloride; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and salts thereof; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, methoxyethyl acrylate, phenyl acrylate, cyclohexyl acrylate, and the like; Methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, methoxyethyl methacrylate, phenyl methacrylate, cyclohexyl acrylate, and the like; Unsaturated ketones such as methyl vinyl ketone, phenyl vinyl ketone, methyl isopurophenyl ketone and the like; Vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate and the like; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, and the like; Acrylamide and alkyl substituents thereof; Unsaturated sulfonic acids such as vinyl sulfonate, allyl sulfonate, metalyl sulfonate, P-styrene sulfonate and their salts and the like;

Styrene and alkyl- or halogen-substituted allyl alcohols thereof, such as methyl styrene and chlorostyrene, and esters and ethers thereof; Basic vinyl compounds such as vinylpyridine, vinylimidazole, dimethyl aminoethyl methacrylate, and the like; Vinyl compounds such as acrolein, methacrolein, vinylidene cyanide, glycidyl methacrylate, methacrylonitrile and the like.

In the preparation of the goofy structure using the monomer, the amount of water introduced into the polymerization system is 3 to 50% by weight, preferably 10 to 30% by weight based on the total weight of the water and the monomer forming the polymerization system. Preferably it is 12-25 weight%. When the amount of water introduced into the polymerization system is 3% by weight or less, the melt viscosity of the polymer melt A is significantly increased, impairing the extruding ability of the melt from the spinneret, so that a natural ripple-like foam structure cannot be obtained. If the amount of water exceeds 50% by weight, the melt viscosity of the melt is lowered conversely and the foamy product is ruptured, which significantly impairs the uniformity of the resulting product.

The polymerization system should be maintained at or above the vapor pressure generated in the polymerization system under polymerization conditions. It is necessary to use the temperature of 120 degreeC, preferably 130 degreeC or more about superposition | polymerization temperature. By satisfying such polymerization conditions, a transparent polymer melt A having fluidity can be obtained. The melt is then formed into a high quality synthetic hull-like structure through extrusion and post-treatment. Of course, the use of polymerization conditions outside the specific ranges described above makes it difficult to reach the objects and effects of the present invention. Considering the decomposition and color change of the resulting melt, the upper limit of the polymerization temperature is 300 ° C. or less, preferably 250 ° C. or less. As for the polymerization pressure, any pressure can be used as long as it is higher than the autogenous pressure, but from an industrial operation point of view, it is generally suitable to polymerize at a pressure of 5 to 55 kg / cm ² .

-선 조사에 의한 중합등의 중합방법을 사용할 수 있다. 특히 중합개시 수단으로서 유용성 또는 수용성 기-발생제로 촉매로 사용함에 의하여 본 발명의 목적과 효과는 유효하게 도달될 수 있다. 이와 같은 유용성 기-발생제에는 예컨대 디-3급-부틸 디퍼록시프탈레이트, 3급-부틸 하이드로 퍼폭사이드, 2,5-디메틸-2,5-디-3급-1부틸 퍼폭시헥신등이 유기과산화물; 4-아조비스-4-시아노펜타노인 아미드, 1-아조비스-1-싸이클로헥산 카보니트릴등과 같은 아조화합물이 포함된다. 수용성 기-발생제로는 과산화수소, 과향산염등을 들 수 있다. 촉매의 사용량은 일반적으로 0.01~5중량%, 바람직하게는 0.1~3중량인 것이 바람직하다.As the polymerization initiation means applied to the polymerization of the present invention, all conventionally known methods can be used. For example, group-high polymerization using group-generating agents such as organic or inorganic peroxides, azo compounds, direct photopolymerization by ultraviolet irradiation, or photosensitization polymerization in the presence of a photosensitizer,

Polymerization methods, such as polymerization by -ray irradiation, can be used. In particular, by using the catalyst as an oil-soluble or water-soluble group-generating agent as a polymerization initiator, the object and effect of the present invention can be effectively reached. Such oil-soluble group-generating agents include, for example, di-tert-butyl diperoxyphthalate, tert-butyl hydroperoxide, 2,5-dimethyl-2,5-di-tert-1 butyl peroxyhexine, and the like. peroxide; Azo compounds such as 4-azobis-4-cyanopentanoin amide, 1-azobis-1-cyclohexane carbonitrile and the like. Examples of the water-soluble group-generating agent include hydrogen peroxide, perchlorate, and the like. The amount of the catalyst used is generally 0.01 to 5% by weight, preferably 0.1 to 3% by weight.

The polymerization time varies depending on the polymerization initiation method, the type and amount of the initiator, the polymerization temperature, and the like, but a time of 10 minutes to 2 hours, preferably 20 minutes to 1 hour is used. Thus, the polymerization reaction according to the present invention can be achieved in a short time is related to the advantage that the synthetic husk of the present invention is manufactured with high production efficiency and supplied at a low price.

In order to modulate the properties of the synthetic golps structure, which is the final product, within the range that does not adversely affect the pressure equalization polymerization of the present invention, known colorants, heat stabilizers, flame retardants, softening agents, antistatic agents ), Fragrances, pigments, antibacterial agents, lubricants, antifouling agents, ultraviolet stabilizers, dyes, deodorants, deglossants and the like can be added to the polymerizing agent. These modifiers can of course be introduced directly into the polymer melts produced by autoclave polymerization.

Substantially molten transparent polymerised melt A prepared according to the invention is prepared at a polymerization conversion rate (monomer; polymer conversion) of 50 to 90%, and has a polymer molecular weight of 45, 000 to 80,000, and therefore is synthesized It is a very suitable starting material for making rushes. Because synthetic pulpy structures made from acrylic polymer derivatives having polymerization conversion and molecular weight within the above range have moderate strength (abrasion resistance) and elastic recovery, and other foam-like structures (surface layers have a corrugated structure) And the inner layer forms a myriad of independent continuous bubbles).

Mixture A contemplated for the production of synthetic pulpy structures is 40-90% by weight, preferably 50-80% by weight of an acrylic polymer (single polymerization of AN, but at least 40%, preferably 60% AN and at least some Obtained by copolymerization of an ethylenically unsaturated compound) with 60 to 10% by weight, preferably 25 to 15% by weight of water.

The mixture B is 40 to 90% by weight, preferably 50 to 85% by weight of the acrylic polymer obtained above, 60 to 10% by weight of water, preferably 25 to 15% by weight, and 60% by weight or less, preferably Is obtained by mixing a plasticizer of 0.5 to 10% by weight or less (based on the total amount of the acrylic polymer and water). If the mixing ratio is outside the suitable range, the melt viscosity suitable for foam extrusion cannot be obtained, resulting in the foamed product bursting and the quality uniformity of the obtained product is clearly impaired. As for the ethylenically unsaturated compound which is a copolymerization component, the above-mentioned compound can be used.

The plasticizers used to obtain the mixture B include organic liquids having a dielectric constant of 30 or more (e.g., formamide, acetamide, glycerin, coolputal, AN, acetonitrile, lactonitrile, ethylene glycol, furophilene glycol, P-nitroaniline, O Nitroaniline and the like) and / or hydrophilic polymers (such as polyvinylalcohol, polyethyleneglycol, polyacrylamide and its derivatives, polyacrylic acid and its salts, polyvinylpyrrolidone, natrium alginate, starch, gelatin, casein, etc.) Included. In particular, when AN, glycerin, or ethylene glycol is used as the organic liquid, and polyvinyl alcohol or polyethylene glycol is used as the hydrophilic polymer, the object of the present invention is advantageously achieved.

As regards the mixing apparatus for obtaining the mixture A or B, there is no particular limitation on these, and any conventional mixing or stirring means can be used.

After the heating operation, the mixtures A or B thus prepared are converted into polymer melts B or C which are substantially in the molten state, respectively. At this time, the heating temperature used should be more than 110 ℃, preferably more than 120 ℃. By this heating operation, a transparent plate polymer melt B or C, which is a fluid, is obtained, and by foaming-extrusion and post-treatment described later, it is formed into a high quality synthetic lump-like structure. The upper limit of the heating temperature should be 300 ° C or less, preferably 250 ° C or less, in consideration of decomposition and color change of the mixture.

Colorants, heat stabilizers, flame retardants, softeners, known as mixtures A or B, in order to modulate the properties of the synthetic pulpsal structure, which is the final product, within a range that does not adversely affect the preparation of the polymer melts B or C according to the invention. Antistatic agents, fragrances, pigments, antibacterial agents, lubricants, antifouling agents, UV stabilizers, dyes, deodorants, deglossants and the like can be added.

The polymer melts B or C thus prepared are useful towards the spinneret while remaining in their state. The pressure of the system in which the melt is present immediately before the pores is then adjusted to 0.5-20 kg / cm ² , preferably 5-15 kg / cm ² to extrude the melt through the pores to convert the melt to a foamy product. Such pressure control is an important factor contributing to the production of synthetic husks suitable for the present invention. If the pressure is 0.5 kg / cm ² or less, the fluid immediately before the hole forms a foam, which increases the viscosity of the fluid, which significantly reduces the molding ability. If the pressure exceeds 20 kg / cm ² , during or shortly after passage of the pores—the sudden fluid forms foam and prevents the formation of a good form of the product. Therefore, it is important to keep the pressure in the system (low pressure-zone) in which the melt exists immediately before the spinneret in the above-mentioned range irrespective of the pressure in the polymerization system. That is, it is important to maintain the pressure between the low pressure zone and the extrusion zone in the above range. As the pressure regulating means, any known pressure drop method can be used. Conventional pressure reducing means includes (I) a method of providing a valve, a gear pump, a kenix mixer, or the like to the fluid transport pipe, (Π) a method of changing the cross-sectional area of the fluid transport pipe from a suitable place, and (III) a passage length of the fluid. (IV) to change the fluid viscosity in the fluid delivery pipe by changing the temperature, (V) to control the amount of fluid introduced into the fluid delivery pipe, and (VI) to the fluid delivery pipe at the outer end. The method of changing the diameter of these, etc. are included. In carrying out the present invention, any combination of these methods can be used. The present inventors cannot fully understand the reason why the above-described pressure control produces foam structures on the natural husk, but the action of the plasticizer present in the water and the water + unreacted monomer or in the water + used AN polymer It can be inferred that foam species are generated in the fluid melt (polymer, melt A or B or C) that can form a uniform, independent continuous bubble. Referring to the spinneret used for the foam extrusion, it may have a single or multiple pores having a diameter of 0.1 to 5 mm, preferably 0.8 to 3 mm. As the extrusion atmosphere, any atmosphere can be used, for example, a pressurized zone in which steam or heated air is present, an atmospheric pressure zone in which water vapor, etc. are present, but the use of air at atmospheric pressure is advantageous among these.

The foamed product extruded as described above is manufactured into synthetic golpul which is very similar to natural pulp by undergoing a spray drawing operation and a foam forming operation in an extrusion atmosphere. The stretching ratio in the spray stretching operation is 1.5 to 10 times, preferably 2 to 7 times. If the draw ratio is outside this range, the surface layer has a corrugated structure in the longitudinal direction and a plurality of bubbles unique to the inner layer, and a synthetic ridged structure that can satisfy the practical strength cannot be produced.

The foamed product thus obtained must be subjected to a heat treatment. Preferable temperature in heat processing is 90 degreeC or more. The heat treatment atmosphere is selected from heated water quenching at 90 to 100 ° C., heated dry air at 90 to 250 ° C. or inert suspending agent or humectant heated to 100 to 250 ° C. or the like. As long as the above temperature range is satisfied, heated rollers or heated plate heating, infrared irradiation or dielectric heating (micro-wave heating) can be used. Such heat treatment is an indispensable step in the manufacture of artificial rushes. This is because this step removes the water and plasticizer in the fluid melt (polymer melts B or C) to enhance the drawing efficiency and produce fine foaming, resulting in the appearance and strength of the foam product closer to natural pulp. It is also possible to perform the stretching operation (cold stretching) simultaneously with the heat treatment. By this stretching, the actual strength (wear resistance) can be increased to a higher range. The stretching ratio in the secondary stretching operation is 1 to 5 times, preferably 1.1 to 3 times.

The foamed product thus heat-treated and stretched as required is then subjected to limited shrinkage or free shrinkage and then cut to a predetermined length to produce the final product synthetic pulp. Such shrinkage treatment further enhances the dimensional stability.

Synthetic hulls produced by the above process are dyed as required. The dyeing treatment is carried out before, during or after the heat treatment.

The pulp-like structure obtained by using such a manufacturing means has an average diameter of 0.2 to 6 mm, an outline density (defined later) of 0.05 to 0.8 g / cm ³ , preferably 0.1 to 0.5 g / cm ³ , and a surface layer. It has a unique corrugated foam structure having a corrugated structure in the longitudinal direction and having an inner layer foam structure. In addition, the present pulpit structure has eliminated all inadequate problems if the conventional pulps shape linear product or natural pulps. Thus, the synthetic ridged structure according to the present invention is remarkable in that it has a wide range of applications such as high quality tatami surfaces, mats, garnets, decorations and the like.

The present invention will be described in more detail by way of examples, with the scope of the invention being not limited by the description of the following examples, and all parts and percentages described are by weight unless otherwise indicated.

The bulk density described in the examples was measured by the following method.

[Definition of Bulk Density]

The bulk density (D) of the synthetic hull-like structure is defined by the following formula.

는 구조물의 외형 단면적이고 N(cm)는 구조물의 길이를 나타낸다. 상기한

는 다음과 같이 얻어진다.Where W is the weight of the structure (g) and N (cm) is the length,

Is the external cross section of the structure and N (cm) is the length of the structure. Above

Is obtained as follows.

Where di (cm) is the outer diameter of the structure, and the measurement is repeated i times at random intervals along the longitudinal direction.

(i = 1 to n)

[Calculation of Bulk Density]

The bulk density was calculated as follows according to the above defined formula.

A 100 cm long rippled structure to be measured is prepared. Measure the outside diameter (d) at 9 measurement points taken at 10 cm intervals along the both ends and length of the sample twice, i.e., at the measurement points described above with a pair of measuring weakeners or micrometers. Is measured by rotating the sample 90 ° in the longitudinal direction.

, 즉 외형단면적(

)을 다음 공식에 따라 얻는다(이때 11개의 측정지점에서의 각개 단면적은 원이라고 가정한다) :Average value of each cross-sectional area from each value (diii = 1-22) measured in this way

, That is, the cross-sectional area (

) Is obtained according to the following formula (where each cross-sectional area at 11 measurement points is assumed to be a circle):

Next, the weight (wg) (length 100 cm) of the sample is counterbalanced to obtain a bulk density (D) from the following formula.

Of course, the larger the value D, the larger the bulk density.

Example 1

Two types of acrylic polymer compositions (mixture A) were prepared by mixing acrylic polymer (90% AN and 10% methyl acrylate) and water as shown in Table I below. Each polymer composition was fed to a known melt-spinning apparatus and melted at 160 ° C. under autogenous pressure. The melt was continuously extruded through a single hole with a diameter of 1.2 mm while maintaining the pressure of the system in which the melt was present immediately before the hole as shown in Table I, and the extrudate was spray-drawn at twice the draw ratio.

The satiety products (four types) were then heat-treated in a heated air stream while stretching at 1.3 times. After dyeing and finishing, they were dried for 10 minutes in a heated air stream at 120 ° C. Next, the satiety product was cut to a length of 1 m to obtain a synthetic chaff-like structure as a final product. The appearance and bulk density of the final product are shown in comparison with that of natural husks.

TABLE 1

As can be seen from Table 1, the synthetic pulp according to the invention is very similar to natural pulp.

Synthetic hulls thus obtained were fed to tatami surface braids to produce tatami surfaces with light weight, excellent moisture absorption, moisture absorption, dyeing and light stability, and very high commercial value. The abrasion test was performed on the tatami of the natural hoop and the tatami of the synthetic hoop according to the present invention. The latter showed very good abrasion resistance.

Example 2

80 parts of the same acrylic polymer and 20 parts of water were mixed with the plasticizers shown in Table 2 (preparation of mixture B). Each mixture was melted by the same heating operation as in Example 1. Next, the melt is continuously extruded into the atmospheric pressure zone through a single hole of 1.3 mm in diameter while maintaining the pressure of the system in which the melt is present immediately before the hole at 60 kg / cm ² , while the extrudate is spray drawn at a draw ratio of 4 times. I was.

The foamed product thus obtained was prepared into a final synthetic husk in the same manner as in Example 1, the properties of which are shown in Table 2.

TABLE 2

Swordsiness = 98

Degree of Polymerization = 500

It can be seen from Table 2 that the quality of synthetic hulls (No. 1 and No. 3) is very excellent.

Meanwhile, the foamed product, which was prepared by the same extrusion operation but did not undergo post-treatment, did not have a foam structure such as natural husk, and could not be braided by an automatic braid because its strength was not sufficient.

As can be seen from the above description, in order to prepare a synthetic lycra-like structure according to the present invention, there is provided a step of preparing an AN polymer composition having the above-described special composition, and extruding the melt thus obtained under the above-described controlled pressure into a foam phase. The step of forming the product and the step of heat treating the foamed product thus obtained must be combined.

Example 3

A continuous polymerization of AN was carried out in a polymerization tank equipped with an anchor stirring blade, a temperature detector tube, a pressure detector tube, and a rekill. The polymerization tank had a stainless steel feed tube attached to its bottom. This supply line was connected to a number of plunger pumps. A needle-shaped valve was attached on the shaft wall of the tank, and a nozzle having a fine hole of 1.3 mm in diameter was attached to the other end of the valve. The flow passage in the nozzle has a cock that can increase or decrease the cross sectional area of the passage. Jacking the polymerization tank is provided with a pipe through which the steam is extruded. Jackel is also equipped with a detector for detecting the temperature and pressure of the melt in the polymerization tank.

Upon initiation of the polymerization, the needle valve was completely closed at first, and then the pump was driven to introduce the monomer mixture and the aqueous solution into the polymerization tank maintained at 135 ° C from the feed pipe.

Monomer mixture: AN / methyl acrylate = 91/9 (raw material flow rate = 12.44 ml / min)

Aqueous solution: contains 8% ammonium, sulfate and 3.2% sodium carbonate (raw material flow rate: 2.36 ml / min)

After the polymerization was progressed, the polymerization tank was filled with polymer in a molten state, and the pressure in the tank was adjusted to maintain the pressure in the tank at 25 kg / cm ² (gauge pressure).

Next, the pressure of the flow passage (the system in which the melt exists) was lowered to 3.0 kg / cm ² by adjusting the diameter of the cock provided between the needle valve and the ball outlet. While maintaining the pressure under these conditions, the melt in the polymerization tank was continuously extruded through the aperture into the atmospheric pressure zone, while the extrudate was spray-drawn at twice the draw ratio. The molecular weight of the melt was 57500 and the polymerization conversion was about 67%.

The foamed product thus obtained was heat-treated while stretching to a length of 1.3 times in a heated air stream at 120 ° C. After dyeing and finishing, the mixture was dried in a heated air stream at 120 ° C. The foamed product was then cut to a length of 1 m to obtain a synthetic chamomile-like structure as a final product.

)과 용적밀도(D)가 천연골풀의 그것과 비교되어 표 3에 나타나 있다.The synthetic hulls thus obtained had a corrugated structure in the surface layer and an excellent foam structure in the inner layer. External cross section of final product (

) And bulk density (D) are shown in Table 3 compared to that of natural husks.

TABLE 3

As can be seen from Table 3, the synthetic pulp according to the invention is very similar to natural pulp.

Synthetic hulls thus obtained were fed to a conventional tatami surface automatic knitting machine to produce a tatami surface. Thus prepared tatami has a very high commercial value because of the light weight, excellent hygroscopicity, dyeing and light resistance. The abrasion test was carried out on tatami mats made of natural husks and tatami mats made of synthetic husks according to the present invention. The latter proved to have better wear resistance than the former.

Example 4

The polymerization was carried out under the same conditions as in Example 3 except that the composition of the monomer mixture was changed to AN1 methyl acrylate = 95/5 and the concentration of sodium bicarbonate was changed to 1.6%. The molecular weight of the polymerization fluid thus obtained was about 56, 600 and the polymerization conversion was about 64.4. After the polymerization tank was filled with the polymer in the molten state, the pressure in the polymerization tank was maintained at 30 kg / cm ² (gauge pressure). Next, by the same operation as in Example 3, the pressure in the flow passage (the system in which the melt exists) from the cock to the hole exit end is changed as shown in Table 4, and the melt in the polymerization tank is continuously extruded through the hole into the atmospheric pressure zone. While the extrudate was spray-drawn at a draw ratio of four times.

The foamed product thus obtained was treated as in Example 3 to obtain a synthetic rumpled structure cut to a length of 1 m, which is the final product.

The appearance, form, and bulk density of the synthetic hulls thus obtained are shown in Table 4 below.

TABLE 4

As can be seen from the results in Table 4, the pressure control according to the present invention has become an important factor for producing a synthetic pulp similar to natural pulp.

Three kinds of synthetic hulls described above according to the present invention and two kinds of synthetic hulls taken as comparative examples were prepared as tatami surfaces, respectively. The former had a similar feel and appearance to natural husks, while the latter both had poor operability and poor commercial value.

Example 5

The following polymerization was carried out using the same polymerization tank used in Example 3.

1.0% n- (heptane and 0.35% 2-mercaptoethanol as chain transfer agent were mixed as a foaming agent and dissolved together with a monomer mixture consisting of 85 parts AN and 15 parts methyl acrylate. % Aqueous solution was prepared (pH = 2.7), and then the feed rate of 11.62 ml / min and 3.18 ml / min was supplied to the polymerization tank using a plunger pump, respectively. The temperature was maintained at 140 ° C. and the pressure at 28 kg / cm ² (gauge pressure).

After the polymerization tank was filled with the polymerization fluid in the molten state, the diameter of the cock provided in the passage between the needle-shaped valve and the hole exit end was adjusted so that the pressure in the passage between the cock and the hole exit end was 7.0 kg / cm ² . While maintaining the pressure at this condition, the melt in the polymerization tank was extruded into an atmospheric zone through a 1.3 mm diameter hole, while the extrudate was spray-drawn at a rate of three times. The molecular weight of the rapeseed melt was 53000 and the polymerization conversion was 71.5%.

The foam product thus obtained was conveyed into heated air at 130 ° C. while stretching to a length of 1.13 times and heat-processed in dried heated air at 140 ° C. The relaxation rate during the heating-process was 0%. The foam product was cut to 1.2 m in length to obtain a synthetic chamomile-like structure as a final product.

Synthetic hulls thus obtained had a volume density of 0.22, and the shape and appearance did not lag behind natural hulls. There was no difficulty in preparing tatami surfaces from the synthetic husks using an automatic braiding machine. The tatami mat thus obtained was particularly excellent in absorbing ability, light stability and elastic recovery, and had a high practical value. On the other hand, the foamed product prepared for the comparative purpose, which was subjected to the same extrusion operation but not post-treated, did not have a similar foam structure to the natural husk, moreover, its strength was insufficient and could not be braided by the automatic knitting machine.

As is evident from the above description, in order to prepare a synthetic golpus structure according to the present invention, the step of preparing the AN polymer composition using the above-described special polymerization conditions, and the melt thus obtained is controlled pressure It is necessary to combine the step of extruding under to obtain a foamy product and the step of heat-treating the foamy product thus obtained.

Claims (1)

As described above in the text, acrylonitrile alone or a monomer mixture composed of acrylonitrile and at least one ethylenically unsaturated compound, wherein water is present in an amount ranging from 3 to 50% by weight, based on the total weight of monomers and water. Preparing an acrylonitrile polymer composition in a substantially molten state by polymerizing at a temperature equal to or higher than 120 ° C. under a pressure equal to or higher than the vapor pressure generated in the polymerization system in the system, and allowing the melt thus obtained to flow toward the spinneret. Adjusting the pressure of the system in which the melt is present immediately before the hole to 0.5-20 kg / cm ² , extruding the melt through the hole to form a foamed product, and Characterized in that it comprises a step of heat-treating.