JPS5850623B2 - grass-like structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new grass-like structure, and more specifically to a synthetic grass-like structure made of an acrylic polymer and whose outer skin structure and internal structure closely resemble natural grass. It concerns structures.

Traditionally, in Japan, tatami mats, Moya, and Hanahagi, etc. made from the rush plant have been popular since ancient times, but it is an undeniable fact that their production has been gradually decreasing in recent years. It is.

This is due to the fact that as areas around natural rice cultivation areas gradually transformed into industrialized areas, air pollution increased and as a result, it became difficult to cultivate and collect high-quality rice straw, and the cultivation of rice grass required a great deal of labor. The cause is said to be that it has become difficult to secure a workforce.

Therefore, it is well known that in recent years, attempts have been made to actively produce substitutes for natural rice grass from synthetic plastics, etc., which are produced in large quantities through industrial production and whose quality is stable.

For example, rugs made of braided hollow or foamed linear bodies such as polypropylene, polyethylene, and polyvinyl chloride have been prototyped and commercially available.In particular, synthetic straw made of polypropylene has the advantages of being inexpensive, strong, and beautiful. It seems that it has become rapidly popular.

By the way, conventional techniques for producing synthetic strawberry from synthetic plastics are disclosed in, for example, Japanese Patent Publication No. 4033/1983 (polypropylene to polyvinyl alcohol) and Japanese Patent Publication No. 45/3/1983.
Publication No. 4778 (foamed polyethylene type), Utility Model Publication No. 45.
-27341 (Polyolefin system), Special Publication No. 1973
-23905 (foamed polyvinyl alcohol, foamed polyvinyl chloride type) and the like.

However, although synthetic plastics such as polypropylene, polyethylene, polyvinyl chloride, and polyvinyl alcohol are cheap and have advantages in mass production, they lack the unique shape, practical performance, etc. that were originally inherent in natural rice grass. It was hard to say that it was better than that.

For this reason, it has been impossible to bring out the advantages of the rush plant, such as its hygroscopicity (water absorption), elastic recovery, dimensional stability, and gentle feel, and there is still much to be done in its use. It did not surpass natural straw.

On the other hand, it is true that tatami mats and the like made of natural straw are not completely free from drawbacks in terms of their performance, and some problems remain in their practical use.

In particular, users of these products will readily agree that they still tend to lack light fastness, dyeability, quality uniformity, abrasion resistance, etc.

Considering the conventional technology, we find that tatami, which can be said to be indispensable to the lives of Oriental people, still contains various problems, and it is possible to improve them by using natural or synthetic materials. We can grasp what is still left.

In order to improve the drawbacks associated with the conventional products as described above, the present inventors conducted extensive research and found that the present inventors have developed a product made of acrylic polymer and having a foamed structure similar to natural straw grass. The inventors have discovered that a synthetic straw-like structure can overcome all the problems of conventional products, and can therefore be advantageously used as a material for tatami mats, etc., and have arrived at the present invention.

It is an object of the present invention to provide a new synthetic grass-like structure.

Other objects of the present invention are appropriate elastic recovery, gentle feel, light fastness, dyeability, quality uniformity, abrasion resistance, water absorption,
It is an object of the present invention to provide an artificial straw-like structure that has excellent moisture absorption properties and can be advantageously used as a raw material for tatami mats, rugs, flower eaves, etc.

Furthermore, other objects of the invention will become apparent from the detailed description of the invention provided below.

The object of the present invention is to produce an acrylic polymer obtained from acrylonitrile alone or from acrylonitrile and at least one ethylenically unsaturated compound, having an average diameter of 0.5 to 5 mm and a bulk density of 0.
．． 05 to 0.8 F/crri, and is achieved by providing a grass-like structure in which the outer layer part forms a wrinkle-like structure and the inner layer part forms a foam-like structure.

Such a synthetic grass-like structure has a wrinkle-like structure in its outer skin layer and a foam-like structure in its inner layer, which has a unique foam-like structure similar to that of a plant "rush". Because of this, it can provide a gentle feel similar to that of a tatami surface made from natural strawberry, and has appropriate water absorption and hygroscopicity due to the high wettability of the acrylic polymer used. It has excellent elastic recovery power and dimensional stability, and further improves quality uniformity, gloss, etc.

Furthermore, due to its material composition (acrylic polymer is used), the artificial straw according to the present invention can be imparted with significantly improved light resistance and dyeability, thereby further increasing its commercial value. be.

Furthermore, the synthetic straw-like structure according to the present invention has the advantage that it is light and easy to handle, and can be easily woven using a conventional tatami facing loom.

As described above, the synthetic grass-like structure according to the present invention has a structure that is not found in artificial grass made of conventional synthetic plastics, due to the synergistic effect of its material composition and its unique shape and form. It can be endowed with various sensory and practical properties that are not possessed even by natural rice grass, and its industrial and social significance is that of a dog.

As mentioned above, the synthetic grass-like structure of the present invention, which has various advantages, is characterized by its foamed structure that closely resembles that of natural grass. For more clarity, Figure 1 a, b, Figure 2 a, b, and Figure 3 a.

This will be explained using the scanning electron micrograph shown in b.

First, Figures 1 a and b show cross-sectional micrographs and longitudinal surface micrographs of the plant ``Igusa'', and Figures 2 a and b show cross-sectional views of synthetic rush obtained from polypropylene linear bodies. A surface photograph and a surface measurement photograph in the length direction are shown.

Figures 3a and 3b show cross-sectional scanning electron micrographs and longitudinal surface scanning electron micrographs of a grass-like structure according to the invention.

What can be clearly understood from these photographic observations is that
Although the straw grass structure according to the present invention is a synthetic product, it forms a unique form that has a wrinkled structure (surface layer) and a foam structure (inner layer), just like natural grass. be.

Of course, it can be easily understood that the conventional polypropylene/grass-like structure does not form such a unique shape or form.

In addition, JSM-U3 model manufactured by JEOL Ltd. was used for the above-mentioned scanning electron micrograph observation.

As described above, the grass-like structure, which is ideal as a material for tatami mats and other materials with excellent sensory and practical performance, can produce unique effects due to the selection of acrylic polymer and its unique foam-like structure. However, it has the above characteristics and has an average diameter of 0.
5-5 doors, more preferably 0.8-4 doors, most optimally 1-2.57 doors, bulk density (defined below) 0.05
~0.8tiI'/cnf, more preferably 0.1
By using a grass-like structure having a P/Cd of ~0.5, the objects and effects of the present invention can be more advantageously achieved.

That is, if the diameter is less than 0.5 mrn or if it exceeds 57n7IL, it is unsuitable for use as a tatami surface material, etc., and is not preferred.

On the other hand, if the bulk density is less than 0.05, the elastic recovery property and practical strength will be insufficient (so-called stiffness), and weaving (making tatami mats) will be difficult. This is undesirable because it becomes difficult to express a gentle feel, and its commercial value is significantly reduced.

Next, a method for producing a grass-like structure made of such an acrylic polymer and having a specific structure in its surface layer and inner layer will be explained below.

That is, it is important to select and use acrylonitrile alone or an acrylic polymer obtained from acrylonitrile and at least one ethylenically unsaturated compound as a starting material for the synthetic strawberry according to the present invention. It is converted into a structure having the desired surface and internal morphology by dry spinning, wet spinning, semi-melt spinning or melt spinning.

That is, in these spinning methods, (I) a heating foaming agent (organic foaming agent, inorganic foaming agent, etc.) is added to the polymer solution or melt.
(II) introducing a volatile liquid to obtain a foamed linear body; (e) blowing air, carbon dioxide or nitrogen gas to obtain a foamed structure; (2)
Alternatively, a method is adopted in which a polymer solution or melt prepared at high temperature and high pressure is extruded (sprayed) into a low pressure region to obtain a grass-like structure, and in any case, the epidermal layer part becomes wrinkled as described above. There are no particular limitations on the manufacturing method as long as it is possible to form a foam-like structure and to manufacture a product in which the inner layer has a foam-like structure.

In particular, specific preferred means for producing the synthetic rice straw according to the present invention are appended here.

For example, 30 to 90% by weight of an acrylic polymer obtained from acrylonitrile alone or acrylonitrile and at least one ethylenically unsaturated compound, 1 to 5% by weight of water,
An acrylonitrile polymer composition obtained by uniformly mixing 6% by weight and 2 to 63% by weight of acrylonitrile is heated under autogenous pressure or higher pressure to melt it, and then the resulting molten Once the pressure of the system where the object exists is set to 0.
5 to 15 kg/ffl, and then extruded through an orifice to a normal pressure region to produce a foamed structure, or 30 to 90% by weight of the acrylic polymer and 70% by weight of water.
An acrylonitrile polymer composition obtained by uniformly mixing ~10% by weight is heated under autogenous pressure or higher pressure to melt it, and then A means for producing a foamed structure by once reducing the pressure to 0.5 to 15 kg/ffl and then extruding it to a normal pressure region through an orifice, or a method consisting of acrylonitrile alone or acrylyl and at least one ethylenically unsaturated compound 1 of the monomer mixture based on the total amount of monomer and water.
Acrylonitrile-based in a substantially molten state obtained by polymerizing at a temperature of 120°C or higher under a pressure higher than the vapor pressure generated in the polymerization system in a system containing water in the range of 0 to 30% by weight. Once the polymer composition was heated to 0.
5~15kg/cr? A method may be adopted in which the L is lowered and then extruded through an orifice into a normal pressure region to produce a foamed structure.

By selecting and using these methods, it has become possible to more advantageously produce a synthetic grass-like structure in which the surface layer forms a wrinkle-like structure in the length direction and the inner layer has a foam-like structure. .

The synthetic strawberry according to the present invention can be produced by the method described above, but the conditions of the above-mentioned production method, such as the degree of pressure drop, orifice diameter, and the amount of acrylic polymer used, must be adjusted within the range of use. By making appropriate selections, the average diameter of the foamed structure can be adjusted to 0.5 to 5 degrees, and the bulk density (defined below)
can be maintained at 0.05 to 0.89/cril, thereby making it possible to further promote the objects and effects of the present invention.

Note that the above-mentioned acrylic polymer includes acrylonitrile alone or acrylonitrile containing at least 40% by weight or more, preferably 60% by weight, as a binder, and the remainder consisting of at least one radically polymerizable ethylenically unsaturated compound. It is a generic term.

Incidentally, the ethylenically unsaturated compounds that can be employed in the present invention include vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, etc.; vinyl chloride and vinylidene chlorides; acrylic acid, methacrylic acid, maleic acid, etc. acids, unsaturated carboxylic acids such as itaconic acid, and their salts; methyl acrylate, ethyl acrylate, butyl acrylate,
Acrylic esters such as octyl acrylate, methoxyethyl acrylate, phenyl acrylate, and cyclohexyl acrylate; Methacrylic esters such as butyl methacrylate, octyl methacrylate, methoxyethyl methacrylate, phenyl methacrylate, and cyclohexyl methacrylate; Methyl vinyl ketones: vinyl formate, vinyl acetate, 7”.

Vinyl esters such as vinyl pionate, vinyl butyrate, and vinyl benzoate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; Acrylic acid and its alkyl substituted products; Unsaturated sulfonic acids such as vinyl sulfonic acid and p-styrene sulfonic acid and their salts: styrene and its alkyl or halogen substituted products such as styrene, α-methylstyrene, and chlorostyrene; allyl alcohol and its esters or ethers; vinylpyridine,
Basic vinyl compounds such as vinylimidazole and dimethylaminoethyl methacrylate; vinyl compounds such as acrolein, methacrolein, vinylidene cyanide, glycidyl methacrylate, and methacrylateryl are used alone or in combination.

Furthermore, as a different embodiment of the present invention, the surface layer and/or inner layer of the synthetic grass-like structure may contain well-known coloring inhibitors, heat stabilizers, flame retardants, softeners, antistatic agents, fragrances, pigments, and mold-proofing agents. It is also possible to introduce modifying substances such as additives, lubricants, antifouling agents, ultraviolet stabilizers, dyes, deodorizing agents, matting agents, etc., partially or completely, by coating, impregnating, or other treatment operations.

Furthermore, it is difficult to list specific examples of the modifying substances that can be applied to the present invention because they are too diverse, so only a few of them will be listed here; however, the present invention is not limited to these examples. Needless to say, it won't.

Namely, lead white, zinc white, dark blue, benzidine orange,
Pigments such as benzidine yellow, copper phthalocyanine green, pearl pigment, etc.: polyoxyethylene octylamine,
Antistatic agents such as enalen oxide adducts of alkylphenols, stearic acid monoglyceride, sorbitan distearate, and trimethyloctadecyl ammonium chloride; Softeners such as octadecylamine acetate, octadecylethylene urea, trimethyldodecyl ammonium chloride, and sorbitan monolaurate; Flame retardants of bisphenol bromide, butane tetrabromide, phthalic anhydride tetrabromide, perchloropentacyclodecane, barium metaborate, methyl acid phosphate, and most of their halogen-containing organic compounds; tributyltin acetate, dimethyldiocarbamate Examples include antifungal agents such as zinc, salicylanilide, phenylmercuric acetate, and bis(trimethyltin) oxide.

It is made of such an acrylic polymer, has a unique foamed structure (the outer skin layer forms a wrinkled structure, and the inner layer has a foamed structure), and has an appropriate diameter and bulk density. The synthetic grass-like structure that has the above-mentioned structure has been able to eliminate all the disadvantages originally inherent in the conventional synthetic grass-like linear structure or the plant "rush", and in the future,
It is noteworthy for its wide range of uses, including high-quality tatami mats, moza, flower reeds, rugs, and materials for decorative items.

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the scope of the present invention is not limited by the description of these Examples.

Further, in the examples, all parts and percentages are expressed on a weight basis unless otherwise specified.

Incidentally, the bulk densities described in the examples were measured by the following method.

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

D-W/((S)XN) Cf? /cyit] Here, Wll) means the weight of the structure N[1), S C1,) means the apparent cross-sectional area of the structure, and N C1,) means the length of the structure.

Incidentally, the above S is determined as follows.

π n 5=(-Σ (di)2)/n Ccr? L)4
□=1 Here, dir (1m) is the length of the grass-like structure.
Ncm ) direction at i locations (i-1 to n
) means the measured apparent diameter of the structure.

Moreover, the bulk density listed in the examples of the present invention was calculated as follows based on the above definition formula.

That is, a grass-like structure (substance to be measured) 100 is first prepared.

Next, the apparent diameter (d) of measurement points (9 locations) graduated at intervals of 10 crrL along both ends (two cut surfaces) of the material and the length of the material was measured twice at different measurement positions. Measure using a caliper or micrometer.

During these two measurements, in the first and second measurements,
It is assumed that the above material is rotated at a central angle of 900 rotations in the outer circumferential direction.

Based on each measured value (di: i = 1 to 22) thus measured, the average value of the cross-sectional area (πdi'/4) of each location, that is, the apparent cross-sectional area (S) is calculated using the following formula (
Calculated assuming that the 11 measurement points of the structure are circular).

On the other hand, the weight (Wl) of the substance to be measured (length 100 cIrL)
) is weighed, and the bulk density D) is determined from the above (S).

Needless to say, the larger the value of D, the lower the bulk density.

Example 1 60 parts of acrylic polymer consisting of 90% acrylonitrile, 10% methyl acrylate, 5% sodium bicarbonate
An acrylonitrile polymer composition was prepared by mixing 12 parts of the aqueous solution and 28 parts of acrylonitrile, and the composition was supplied to a known melt spinning machine and heated and melted at 140° C. under autogenous pressure.

Thereafter, the melt was extruded into a normal pressure region through an orifice with a diameter of 1.3 mm, and the extrudate was further stretched 1.2 times under dry heat at 120°C to obtain a final product, a synthetic straw-like structure. .

The synthetic straw obtained in this way had a wrinkled structure on the surface layer and exhibited a good foaming state inside.

Also, the apparent cross-sectional area of the final product (g mentioned above)
Table 1 shows the average diameter and bulk density 0 in comparison with natural rush.

From the results in Table 1, it can be seen that the synthetic rush according to the present invention is extremely similar to the plant "rush".

Furthermore, the synthetic straw obtained in this way was then fed to a known tatami facing loom to produce a tatami facing.

The obtained tatami surface was light and had excellent hygroscopicity, water absorption, dyeability, light resistance, etc., and had extremely high commercial value.

When natural tatami mats and tatami mats made of synthetic straw according to the present invention were subjected to wear tests, it was found that the tatami mats according to the present invention had much better wear resistance than natural tatami mats.

Example 2 Four types of acrylonitrile polymer compositions were prepared by mixing an acrylic polymer consisting of 60% acrylonitrile and 40% vinylidene chloride and water as shown in Table 2, and feeding them to the melt spinning machine of Example 1. The mixture was heated and melted at 160° C. under autogenous pressure.

After that 1. : Extruded into a normal pressure region through a single orifice with a diameter of 1 ffl, the extrudate was further stretched 1.1 times in a humid heat atmosphere at 100°C, and dyed and finished to obtain four types of synthetic straw-like structures as final products. .

Table 2 shows the shapes, forms, and bulk densities of the four types of synthetic rice grass thus obtained.

From the results in Table 2, it is clear that the synthetic straw grass with the bulk density recommended for the present invention can be a material that can give an appearance and feel more similar to tatami mats made of natural "Igusa", and does not cause problems in paper processing. I can understand that.

Furthermore, when we evaluated the sensory performance of conventional synthetic tatami mats made of polypropylene linear bodies with a bulk density of 0.3, we found that they were inferior in appearance, hygroscopicity, water absorption, etc., as well as a gentle feel. Met.

[Brief explanation of the drawing]

Figure 1 a and b show cross-sectional scanning electron micrographs and longitudinal surface scanning electron micrographs of the plant "Igusa", and Figure 2 a and b are obtained from polypropylene linear bodies. A cross-sectional scanning electron micrograph and a surface measurement photograph of synthetic rush are shown. Furthermore, FIGS. 3a and 3b show cross-sectional scanning electron micrographs and longitudinal surface scanning electron micrographs of the grass-like structure according to the present invention. Note that all images were taken at a magnification of 50x.

Claims (1)

[Claims] 1 Consisting of an acrylic polymer obtained from acrylonitrile alone or acrylonitrile and a small amount (both of which are obtained from one type of ethylenically unsaturated compound, with an average diameter of 0.5 to 5
and has a bulk density of 0.05 to 0.8? /crd
A grass-like structure in which the outer layer part forms a wrinkle-like structure and the inner layer part forms a foam-like structure.