JPH0814067B2 - Felt-shaped molded article and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention comprises a fiber cotton and a resin binder, the outermost surface of which is a smooth surface with few napped fibers, and the surface of the fiber cotton is firmly fixed with a resin binder. It is a high density layer with good surface strength, and the inside integrated with this surface part is a flexible low density layer in which fiber cotton is warmly fixed with a resin binder, and felt with good surface strength and cushioning property. And a method for manufacturing the same. Due to the above-mentioned characteristics, this felt-like molded article has good use durability and cushioning property, and is most suitable as a cushioning material for beds, cushions, carpets, tatami mats, packaging and other applications.

<Prior Art> The felt-like molded article of the present invention belongs to the category of conventional thick nonwoven fabrics, and particularly corresponds to a dry nonwoven fabric using a resin binder. Conventionally, in addition to the above-mentioned non-woven fabrics, conventionally, non-woven fabrics include wet fabrics using a resin binder, needle punching non-woven fabrics, hydroentangled non-woven fabrics, melt blown non-woven fabrics, etc., and their manufacturing methods are different, and each product has its own characteristics. However, in these conventional non-woven fabric manufacturing methods, it is difficult to firmly fix the resin only on the surface portion, needle punching, or hydroentanglement, and even if it can be done, these treatments alone do not sufficiently fix the surface portion. Because there is
As in the present invention, a non-woven fabric having an integral structure having a high density high density layer having a smooth surface as the outermost surface with a few napped fibers and good surface strength, and an elastic low density layer inside is not prepared.

Therefore, when using a conventional thick non-woven fabric as a cushioning material for beds, etc., apply a cloth or a thin non-woven fabric with a firm tissue to the surface of the relatively soft and elastic thick non-woven fabric, It is used after being reinforced.

A thin non-woven fabric, which is formed by increasing the surface density after needle punching and adhering only to this part is described in Japanese Utility Model Publication No. 61-82991. JP-A-51-139971 discloses a method in which webs having different densities are individually produced by changing the ratio, and a laminate having a high-density web as an outer layer is impregnated with a thermosetting emulsion exhibiting bulkiness and porosity. Found in the issue.

<Problems to be Solved by the Invention> However, in such a conventional method, since there is no integration between the surface reinforcing material and the thick non-woven fabric, disadvantages such as poor use durability and poor cushioning property occur. There are also drawbacks such as higher cost and poor productivity. The present invention provides a felt-like molded article having a completely new structure and a method for producing the same, which solves the above problems at once.

<Means for Solving the Problems> The present invention is a felt-like molded article (1) comprising a fiber cotton (4) and a resin binder (5), which comprises a hard surface layer (2).
And a soft elastic core layer (3) which are continuously and integrally formed.

Furthermore, the felt-like molded product (1) is composed of 60 to 90% by weight of fiber cotton and 40 to 10% by weight of a resin binder, and has an apparent density of 0.06 to 0.3 g / cm ³ and a thickness of 3 to 50 mm, compression elastic modulus is 50% or more, and at least 0.5 mm or less in thickness forms a hard surface layer (2), and the surface layer (2) is a surface on which fiber cotton is firmly fixed with a resin binder. It forms a high-density layer with good strength, and its apparent density is 0.08.
Was ~0.4g / cm ^3, a continuous integral soft elastic core layer (3) is a low density layer cotton fibers with loose fixed resilient resin binder the surface layer (2), in particular, at least The apparent density occupies more than half of the thickness of the entire molded product and the apparent density is
It is characterized in that it is as low as 0.05 to 0.25 g / cm ³ and that the apparent density ratio between the surface layer (2) and the soft elastic core layer (3) is 1.1 to 2.0.

The preferred method for producing the felt-like molded article of the present invention is as follows. That is, 40 to 60 to 90% by weight of fiber cotton mass
After 10% by weight of a resin binder has been applied, the fibers are opened and spread into layers to form a fiber mat (6), and then the fiber mat (6) is used at the melting point of this binder or a temperature range 110 ° C higher than the melting point and at the time of molding. In the change of the morphology, the compression rate is 97 to 50% and the compression recovery rate at the time of decompression is 5 to 60%. In the state where the compression recovery rate of 5) is 5 to 60%, the hard surface layer (2) and the soft elastic core layer (3) on the front and back are continuously cooled by cooling to a temperature below the melting point of the resin binder and immobilization. It is characterized by being integrally molded.

In describing the present invention in more detail, a method of measuring physical property values will be described. The pressure measurement of the felt-shaped molded product and a part thereof is performed by a dial gauge type thickness measuring device (pressure load 50 g / pressure load) according to JIS-L-1096. cm ² ), and the thickness of the initial fiber mat and the compression gap for calculating the compression ratio during molding were measured with a steel ruler, calipers or a gap gauge. A sample for measuring the apparent density of the surface and the inside of the felt-like molded product was prepared by disassembling each cross-section of this product with a cutter. Further, in the definition of terms, compression ratio = (fiber mat thickness-compression gap) ÷ fiber mat thickness × 100, compression recovery ratio = felt-shaped molded product thickness ÷ fiber mat thickness × 100. Further, the compression elastic modulus and the burst strength of the felt-like molded article were measured according to JIS-L-1096, and the tensile strength and the tear strength were measured according to JIS-L-1085.

The present invention will be described in more detail with reference to the drawings. The felt-like molded article (1) having good surface strength and cushioning property of the present invention comprises 60 to 90% by weight of fiber cotton (4) and 40 to 10% by weight of resin binder (5). If the amount of the fiber cotton (4) is 60% by weight or less, that is, if the amount of the resin binder is 40% or more, the felt-like molded product becomes hard and the cushioning property deteriorates. Further, when the amount of fiber cotton is 90% by weight or more, that is, the amount of resin binder is 10% by weight or less, not only the surface strength of the surface portion but also the internal strength is reduced and the practicality is lost. Note that part or all of the resin binder may be replaced with heat-fusible fiber cotton. Next, the overall thickness of the felt-like molded article (1) of the present invention is 3 to 50 mm. 3m
If it is less than m, it is too thin and it is difficult to produce an apparent density difference between the surface and the inside, and the cushioning property is not good. On the other hand, if it is 50 mm or more, it is too thick and heat is not easily transferred to the central portion during molding, and the fiber cotton is not fixed well by the resin binder (5), resulting in poor strength. The overall apparent density is 0.06 to 0.3 g / cm ³ . 0.06g /
If it is less than ³ cm ³ , the overall strength, surface strength and cushioning property will be insufficient, and if it is more than 0.3 g / cm ³ , it will be too hard and the cushioning property will be poor.

Next, the greatest feature of the present invention is that the outermost surface is a smooth surface with a small amount of napped fibers that is firmly fixed with a resin binder in which the fiber cotton is half-coated, and at least the surface portion within a thickness of 0.5 mm is made of fiber cotton. That is, the high-density layer firmly fixed with the resin binder is formed. The semi-coated smooth surface and high-density layer produce excellent surface strength. This dense layer on the surface has a thickness of 0.5 mm or more, often ranging from 1 to 2 mm. The apparent density of the hard surface layer (2) is 0.08 to 0.4 g / cm ³ . If the apparent density is 0.08 g / cm ³ or less, it is too soft and the surface strength is poor, and if it is 0.4 g / cm ³ or more, the surface is too hard and the cushioning property deteriorates.

Furthermore, the second feature of the present invention is that the hard surface layer (2) and the soft elastic core layer (3) having an integral structure are elastic low density layers in which fiber cotton is loosely fixed with a resin binder. The apparent density of the central part, which occupies at least 1/2 of the total thickness, is 0.05 to 0.25 g / cm ³ which is significantly lower than that of the surface part. If the apparent density is less than 0.05 g / cm ³ , the internal fibrous structure will not be sufficiently fixed and will easily collapse, and it will be too soft and the cushioning property will deteriorate. Also, 0.25g / cm
^When it is ³ or more, the soft elastic core layer (3) is too hard and the cushioning property is deteriorated.

Furthermore, the third feature of the present invention is the density balance between the hard surface layer (2) and the soft elastic core layer (3), especially the central part of the latter, and an apparent density ratio of 1.1 to 2.0 is suitable. If the apparent density ratio is 1.1 or less, the difference in density between the two layers is too small, and the overall difference is too high and the cushioning property is poor, or conversely it is too soft and the surface strength is insufficient, resulting in deterioration in use durability. If the apparent density ratio is 2.0 or more, the difference in density between the two layers is too large, and only the hard surface layer (2) becomes too hard and the cushioning property is deteriorated, or the soft elastic core layer (3) is too soft. Is easy to collapse. As described above, the felt-like molded product (1) in the optimum apparent density range has a compression elastic modulus of 50% or more, and has optimum cushioning properties as a cushioning material. It should be noted that the composition of all layers is such that there is a low-density soft elastic core layer (3) immediately below the high-density hard surface layer (2) and the boundary is often clear, but the high-density hard surface layer (2) In some cases, the boundary between the low-density soft elastic core layer (3) and the low-density soft elastic core layer (3) gradually decreases, and the boundary is not clear.

The fiber cotton (4) used in the present invention is synthetic fiber such as polyester fiber, nylon fiber, acrylic fiber, polyolefin fiber and vinylon fiber, chemical fiber such as rayon fiber and acetate fiber, natural fiber such as cotton, wool, silk and hemp. Any of these may be used, or mixed use may be performed. These fiber cottons (4) used in the present invention are not limited to those obtained by using regular raw materials, but also waste cotton, waste thread, waste cloth generated in spinning process, non-woven fabric manufacturing process, dyeing process, sewing process, or the like. Collected waste cotton obtained by opening the above clothing may be used. Cotton is opened using open fibers, then opened using a machine such as a wrapper or weber, and spread into a layer with a predetermined thickness to form a fiber mat (6).
And

The resin of the resin binder (5) used in the present invention may be a commercially available thermosetting resin or thermoplastic resin which is usually used. Examples of the thermosetting resin include phenol resin, and examples of the thermoplastic resin include polyethylene resin, polypropylene resin, polyester resin,
Nylon resin, polyurethane resin, polyvinyl chloride resin, epoxy resin, polystyrene resin, SBS, NBR, etc. are available. The shape of the resin binder used is powdery, with a diameter of 3 to
It is used in the form of 10 mm small blocks, fibers, nets, and liquids dissolved or dispersed in a solvent. The method of use depends on the shape of the resin binder (5), and during any step from the opening to the production of the fiber mat, a method of spraying a powder on the cotton fiber (4), a method of spraying a liquid, and a coating method. There are a method, a method of dipping, a method of mixing in the fiber mat (6), and the like. When a plurality of fiber cottons having different melting points are used, the fiber cotton on the low melting point side can be used as a resin binder or as a part thereof. What is important in selecting the resin binder (5) is to select a resin having a lower melting point than the melting point of the main fiber cotton (4).

It is to be noted that a part of the object of the present invention is to provide a felt-like molded article having a surface portion having a higher density than that of the inside thereof. It is also effective to increase it in advance. One example of such a method is a method in which a fiber mat having the same resin binder concentration as that of the surface portion is formed, and a resin binder powder or liquid is placed on the surface of the fiber mat. Further, a colorant, an antioxidant, a hygroscopic agent, a deodorant, a bulking agent and the like can be added to the fiber mat in advance.

Next, the preferable heating and pressure molding conditions in the present invention will be described. Molding is performed using a press machine. The press machine may be a discontinuous flat plate press machine, a continuous roll type press machine, or a belt type press machine. A metal plate type, steel belt type, or roll type press equipment for cooling that smooths the surface and cools and fixes the shape at a preferable compression recovery rate (preferred thickness) is required after the pressing step by these pressing machines. is there. In the heat and pressure molding, the heat and pressure conditions are selected so that the resin binder is melted and the fiber cotton is difficult to be melted, and the temperature and pressure effect applied to the surface portion of the fiber mat is stronger than the temperature and pressure effect applied to the central portion. For that purpose, the heating equipment is a method that gradually transfers heat from the surface of the fiber mat to the inside by heat conduction from the heat press, and heats the press and the surface of the fiber mat with secondary heat from the infrared heater and far infrared heater. A method of gradually transferring heat from the surface of the fiber mat to the inside is effective. A method of heating the surface and the inside almost uniformly by convection such as hot air heating is not preferable. However, a combined system in which the fiber mat is preheated by hot air or the like and finally heated by the hot press machine is effective. Specifically, in the range of 60 to 90% by weight of the fiber cotton mass, the melting point of the resin binder of 40 to 10% by weight or the temperature range 110 ° C higher than the melting point, and in the morphological change of the fiber mat (6) during molding, The composition is heated and pressed using the press under the conditions of temperature, pressure and time such that the compression rate is 60 to 96% and the compression recovery rate when decompressed is 50 to 5%. The compression recovery rate of the fiber mat is kept in a form of 50 to 5% with a press facility, and it is fixed by cooling to a temperature below the melting point of the resin binder while applying pressure or surface friction. If the molding temperature is below the melting point, a firmly fixed molded product cannot be made, and it burns and emits a foul odor at a temperature higher than 110 ° C above the melting point. Also, if the compression rate is 96% or more and the compression recovery rate is 5% or less, the whole becomes too hard and the cushioning property is lost, and if the compression rate is 60% or less and the compression recovery rate is 50% or more, it is too soft and the surface strength is high. Is insufficient and durability in use is reduced. The factors that satisfy the above optimum conditions are the thickness of the fiber mat, the apparent density, the molding temperature, the compression rate (the temperature, pressure, thickness setting, time, etc. during molding are involved), and the compression recovery rate after molding ( It is related to the compressibility at the time of molding, the thickness setting of the press equipment at the time of cooling, etc.), and the result of the synthesis of the conditions of these factors is the quality of the molded product. The optimum conditions other than the pressure and time during molding are as described above. As for the pressure and time conditions, the pressure and time at which the optimum compression rate and the optimum compression recovery rate are achieved are selected in consideration of the influence of temperature. Pressure is 0.
It can be selected from the conditions of 1 to 100 kg / cm ² and time of 1 to 300 seconds.
Further, as an advantageous method for obtaining the optimum compression rate and compression recovery rate, a thickness setting for maintaining a predetermined gap between the upper and lower press plates, rolls or belts at the time of heat and pressure molding and at the time of cooling and fixing. There is a method to install a device and a spacer. By using these devices, the optimum compression rate and compression recovery rate can be obtained even if the molding temperature, pressure, and time conditions deviate slightly from the optimum conditions. Note that the gap set value adopted during heat molding and the gap set value adopted during cooling fixation may have different thicknesses.

In addition to the method of carrying out the heat and pressure molding in one step as described above, a so-called two-step molding method in which preliminary molding is carried out under mild heat and pressure conditions and then main molding is carried out as described above can also be carried out. In this case, the compression rate (that is, thickness) of the first stage is set to be equal to or higher than the compression recovery rate in the second stage, and in the second stage, the above-mentioned optimum compression rate is applied to the thickness before the first stage molding And, the condition that the compression recovery rate is obtained is adopted. The advantage of the two-step molding method is that a fiber mat having a relatively stable morphology is obtained in the first step, so that it is easy to handle in the second step of main molding, and a molded article having a shape other than a flat plate shape. There is also an advantage that it can be easily made.

<Operation and Effect of the Invention> The felt-like molded article (1) of the present invention can be produced only by the raw material, raw material composition and heating and pressurizing conditions of the present invention. That is, the resin binder (5) is applied to the fiber cotton (4) to open the fiber,
A fiber mat (6) made by expanding into a layer having a predetermined thickness,
The resin binder (5) is melted, the fiber cotton (4) is difficult to melt, and the temperature and pressure effect applied to the outermost surface of the fiber mat is stronger than the temperature and pressure effect applied to the central part. After that, by performing pressure bonding or friction cooling fixing treatment to obtain a dense smooth surface, the cotton wool (4) is firmly fixed on the outermost surface portion with the resin binder (5) and has a smooth surface with few napped fibers. The surface is a high-density layer in which the fibers are firmly fixed with a resin binder and has a good surface strength, and the fiber cotton (4) is loosely fixed with a resin binder (5) inside the hard surface layer (2). It is a low-density layer having a density lower than the apparent density of (1) and elasticity, and a felt-like molded product having a composition and a structural durability not found in conventional products and good cushioning properties.

<Examples> The embodiments of the present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

Example 1 Polyester cotton mixed cloth waste generated in the sewing process was hung on open fibers to produce waste cotton. Polyethylene resin powder having a melting point of 135 ° C. was mixed almost uniformly in the obtained waste cotton in an amount such that the weight ratio of fiber / resin was 4/1, and then a simple card was used to produce a fiber mat (6). This fiber mat (6) had a thickness of 60 mm, an apparent density of 0.028 g / cm ³ , and was in a fluffy state.

Then, the fiber mat (6) was subjected to flat plate heating and pressurizing by the following method. First, this fiber mat (6) was placed between two chrome-plated iron plate molds. In addition, in order to keep the thickness of the fiber mat (6) constant at the time of molding at the four corners between the two flat plate molds, and to provide a difference in heating and pressing effect between the outermost surface portion and the inside. A small piece of iron plate having a thickness of 13 mm was placed as a spacer. By installing the spacer, the proper temperature and pressure range at the time of molding is widened, and further, the outermost surface of the fiber mat (6) is easily subjected to the heating and pressurizing effect, and the inside, particularly the central part is less likely to be subjected to the heating and pressurizing effect. It will be convenient. Next, an iron flat plate mold with the above fiber mat (6) sandwiched was placed on the surface plate of a hydraulic flat plate heat press machine heated to 210 ° C. in advance and pressed at a pressing force of 30 kg / cm ² for 60 seconds. (Compression rate
78%), then immediately move the iron plate mold sandwiching this fiber mat and spacer to another water-cooled cooling press machine and apply pressure.
After cold-pressing at 5 kg / cm ² for 120 seconds, it was taken out.

The obtained flat-plate felt-like molded product (1) had an overall thickness of 15 mm (compression recovery rate of 25%) and an apparent density of 0.11 g / cm.
³ , the outermost surface is a smooth surface with few napped fibers firmly fixed with a resin binder with a half-fiber surface, and a thickness of about
A high density layer with good surface strength is formed by firmly fixing the fiber cotton with a resin binder on the surface of 1 mm, and the apparent density of this part is 0.15 g / cm ³ , and inside the fiber cotton An elastic low-density layer in which (4) is loosely fixed with a resin binder (5) is formed, especially in the central portion (thickness
The apparent density of 8 mm) was 0.08 g / cm ³ .

As shown in Table 1, this felt-like molded product (1) has various physical property values superior to those of conventional products. The surface strength was determined by a cellotape peeling test using a special method. The test method is shown in the footnote of Table 1.

The felt-like molded product (1) has excellent use durability and cushioning property due to the above-mentioned properties, and is optimal as a cushioning material for beds and cushions.

Comparative Example 1 Using the same fiber mat as in Example 1, this fiber mat was sandwiched between a pair of upper and lower mesh conveyor belts made of iron wire, and passed through a hot air treatment chamber preheated to 190 ° C. for 240 seconds. . The thickness setting device was set so that the gap between the upper and lower conveyor belts would be 13 mm when passing through the room, and the fiber mat was heated and pressed by pressing the conveyor belt with a large number of unheated press rolls. The compression rate at this time was 78%. After passing through the room, cool the fiber mat by air cooling and take it out from the conveyor belt,
mm (compression recovery rate 30%) and an apparent density of 0.094 g / cm ³ were obtained, and a felt-like molded product was obtained. In this felt-like molded product, the hot air almost uniformly passed not only to the surface of the fiber mat but also to the inside of the molded product during the molding process. Further, since the mesh-like pressure was applied instead of the surface condition, the surface portion and the inside were The difference in apparent density cannot be made and the cushioning property is inferior.Fixing of the fibers on the outermost surface and the surface portion by the resin binder is also inadequate. . Table 1 shows various physical properties of the felt-like molded product.

Since this felt-like molded article has insufficient surface strength to be used as a cushion material for a bed, a cloth or a thin non-woven fabric having a firm structure is attached to the surface to reinforce the surface strength.

Comparative Example 2 The same fiber mat as in Example 1 was used, and the same heat pressing machine as used in Example 1 and the two chrome-plated iron flat plate molds were used for heat molding treatment. However, no spacer was used. That is, a flat iron plate with a fiber mat sandwiched on a surface plate of a hydraulic flat plate heat press machine heated to 210 ° C. in advance and heat pressed for 60 seconds at a pressing force of 50 kg / cm ² (compression rate 96.7% ) Next, the iron plate mold sandwiching this fiber mat is immediately transferred to another water-cooling type cooling press machine to apply a pressure of 5k.
It was taken out by cold pressing for 120 seconds at g / cm ² . The obtained flat-plate felt-like molded product has a thin overall thickness of 2.5 mm (compression recovery rate of 4.2%) and an apparent density of 0.68 g / cm ^{3, which} is a high density and there is no difference in density between the surface and the inside. , Veneer plate-like hard material, not suitable for cushioning material.

Example 2 The felt-like molded article (thickness 18 mm, apparent density 0.94 g / cm ³ ) produced in Comparative Example 1 was used, and this was the same hot press machine as in Example 1 and two chrome-plated iron flat plate molds. And thickness
Using the 13 mm iron plate small piece spacer, the same heat and pressure molding conditions as in Example 1 (temperature 210 ° C., pressure 30 kg / cm ² , time 4
0 seconds) and the same cooling press conditions as in Example 1 (pressing force 5 kg)
/ cm ² , for 120 seconds). The felt-like molded product thus obtained has a thickness of 14 mm, an overall apparent density of 0.12 g / cm ³ , and a surface layer (thickness 1 mm) having a dense outermost surface with few napped fibers has an apparent density. It is as high as 0.17 g / cm ^3, and the elastic low density layer inside it is especially in the central part (thickness
(8 mm) had an apparent density as low as 0.09 g / cm ^3, and had an appearance, cross-sectional structure and physical property values that were substantially the same as those in Example 1. The physical properties are shown in Table 1.

As described above, this product has good use durability and cushioning properties due to the same physical properties as those of Example 1, and is optimal as a cushioning material for beds, cushions and the like.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of the felt-like molded article of the present invention, FIG.
The figure is an enlarged cross-sectional view of the fiber mat before molding. (1) Felt-like molded product, (2) Hard surface layer, (3) Soft elastic core layer, (4) Fiber cotton, (5) Resin binder, (6) Fiber mat

Claims (2)

[Claims] 1. A felt-like molded article comprising a fiber cotton (4) and a resin binder (5), wherein a hard surface layer (2) and a soft elastic core layer (3) are continuously and integrally formed. , The felt-like molding (1) is 60 to 90% by weight in all layers
Fiber cotton (4) and 40 to 10% by weight resin binder (5)
The molded product has an apparent density of 0.06 to 0.3 g / cm ³ , a thickness of ³ to 50 mm, a compression elastic modulus of 50% or more, and at least a thickness of 0.5 mm or less forms the hard surface layer (2). The hard surface layer (2) forms a high-density layer having good surface strength in which the fiber cotton (4) is firmly fixed by the resin binder (5), and the surface layer has an apparent density of 0.08 to 0.4 g / cm ³ , and the soft elastic core layer (3) continuously integrated with the surface layer (2) has elastic low density in which the fiber cotton (4) is warmly fixed by the resin binder (5). The layer occupies at least 1/2 of the thickness of the entire molded product, and the apparent density is 0.05 to 0.25 g / cm ^3.
And a felt-like molded article characterized by having an apparent density ratio of 1.1 to 2.0 between the hard surface layer (2) and the soft elastic core layer (3). 2. A mass of fiber cotton (4) of 60 to 90% by weight is provided with 40 to 10% by weight of a resin binder (5), opened, and spread into layers to form a fiber mat (6), In the temperature range of the melting point of the resin binder (5) or 110 ° C. higher than the melting point, and in the morphological change of the fiber mat (6) at the time of molding, the compression rate is 60 to 96% and the compression recovery rate at decompression is 50 to It is heated and pressure-molded under the conditions of temperature, pressure and time of 5%, and immediately decompressed, and the compression recovery rate of the fiber mat (6) is 50 to 5%. A method for producing a felt-shaped molded article, characterized in that the hard surface layer (2) on the front and back sides and the soft elastic core layer (3) are continuously integrally molded by cooling to a temperature and fixing.