JP2016065321A - Knitted fabric having three-dimensional structure and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a knitted fabric having a three-dimensional structure with an improved cushion property and to provide a method for producing such a knitted fabric having a three-dimensional structure.SOLUTION: The knitted fabric having a three-dimensional structure comprises front-side and back-side knitted fabrics and a connecting yarn connecting them. The connecting yarn is made of synthetic fibers having a melting point of 220-270°C according to a DSC method. The front-side and back-side knitted fabrics are made of synthetic fibers, and 0°C≤(a melting point of the connecting yarn according to a DSC method)-(a melting point of the front-side and back-side knitted fabrics according to the DSC method)<30°C. The knitted fabric having a three-dimensional structure has a pressing pressure of 85-150 kgf when compressed into the thickness of 75% according to a JIS K6400-2 E method (press area: 314 cm; compression speed: 100 mm/min). The method for producing a knitted fabric having three-dimensional structure includes heat-treating a three-dimensional knitted fabric comprising front-side and back-side knitted fabrics and a connecting yarn connecting them in a heating furnace set at a temperature lower by 20-50°C than a melting point according to a DSC method of a material of the connecting yarn.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a three-dimensional knitted fabric excellent in restoring property after compression, that is, sag resistance, and a method for producing the same.

  In recent years, a three-dimensional knitted fabric made of front and back knitted fabrics and connecting yarns connecting them has been used as a material for cushion materials. Such a three-dimensional knitted fabric is knitted with a double raschel machine, a double circular knitting machine or the like as described in Patent Document 1, for example, and then subjected to refining and tentering heat setting treatment on the knitted structure. It is manufactured by carrying out (paragraph numbers [0007], [0015], [0016]). The tentering heat setting process is generally performed at a temperature of about 170 to 180 ° C.

  By the way, one of the physical properties required for the cushion material is “no sagging”. For example, Patent Document 2 proposes a cushion material that does not easily sag even at a high temperature of 70 ° C. The cushion material disclosed in Patent Document 2 is composed of a thermosheathed composite fiber and a base material fiber having a core-sheath structure, and is integrally formed by thermoforming and substantially point-joining the base material fiber with the thermoadhesive composite fiber. (Claim 7). The thermal bonding fiber is configured as a composite fiber composed of at least two components, and an aliphatic polyester component having a melting point of 130 ° C. or higher and 200 ° C. or lower is exposed at least on a part of the fiber surface, and the other component has a melting point of 190 ° C. It consists of an aromatic polyester component having a temperature of from ℃ to 230 ℃ (Claim 1). Also in the manufacture of the cushion material disclosed in Patent Document 2, the temperature at the time of thermoforming is 180 ° C. (paragraph number [0058]).

  Thus, conventionally, it has been believed as a common sense that about 180 ° C. is appropriate as the heat treatment temperature of the fiber whose material is polyester.

JP 2004-204372 A JP 2003-268632 A

  The inventor has continued research for improving the cushioning performance of the three-dimensional knitted fabric, in particular, the sag resistance. And, during the manufacturing process of the three-dimensional structured knitted fabric, the temperature of the heat setting process was determined to be about 180 ° C for the material used at the time when the manufacturing of such a three-dimensional structured knitted article was started. However, in relation to the material of the connecting yarn used (more specifically, the melting point), there exists a heat setting temperature that can enhance the cushioning performance (specifically, the strain compression strength) of the three-dimensional knitted fabric. The present invention was completed by continuing research on the relationship between the material of the connecting yarn and the heat setting temperature.

That is, the present invention is a three-dimensional knitted fabric composed of front and back knitted fabrics and connecting yarns connecting them, and the connecting yarns are made of synthetic fibers having a melting point of 220 to 270 ° C. according to the DSC method. Made of synthetic fiber and 0 ° C. ≦ melting point of connecting yarn by DSC method−melting point of DSC method of front and back knitted fabric <30 ° C., and compression of 75% thickness of three-dimensional knitted fabric by JIS K6400-2 E method The knitted fabric has a pressing pressure (pushing area: 314 cm ² ; compression speed: 100 mm / min) of 85 to 150 kgf.

The connecting yarn is a monofilament yarn, and its thickness is preferably 800 to 2,000 denier (888 to 2,220 dtex), and the density of the connecting yarn is preferably 300 to 600 yarns / 25 cm ^2. .

  The material of the connecting yarn and the material of the front and back knitted fabrics may be the same or different. An example of the material for the connecting yarn and the knitted fabric on the front and back is aromatic polyester.

  Further, the present invention comprises front and back knitted fabrics and connecting yarns connecting them, the connecting yarns are made of synthetic fibers having a DSC melting point of 220 to 270 ° C., and the front and back knitted fabrics are made of synthetic fibers and 0 ℃ ≦ melting point of DSC method for connecting yarn−melting point of DSC method for front and back knitted fabric <30 ° C., heat set to a temperature 20 to 50 ° C. lower than the melting point of DSC method for the material of connecting yarn The present invention relates to a method for producing a three-dimensional knitted fabric characterized by performing heat treatment in a furnace.

  In the present specification, “three-dimensional knitted fabric” refers to one that has not been subjected to heat treatment, and “three-dimensional knitted fabric” refers to one that has been subjected to heat treatment.

  The set temperature of the heat furnace is 20 to 50 ° C. lower than the DSC melting point of the material of the connecting yarn, but the temperature is within that range, and heat treatment is performed in the heat furnace set to 190 ° C. or higher. Is preferred.

  According to the present invention, a three-dimensional knitted fabric excellent in strain compression strength and compressibility (that is, sag resistance) and a method for producing the same are provided.

  The three-dimensional structure knitted fabric of the present invention is very light and excellent in sag resistance. Therefore, the three-dimensional knitted fabric is useful as a cushioning material for a chair or the like in a field requiring low weight, such as a vehicle or an aircraft. It is. Moreover, since it is excellent in sag resistance, that is, it is durable, Therefore, since it can be used over a long period of time, as a result, this invention contributes to cost reduction of a chair etc.

It is a graph which shows the relationship between the heat processing temperature of a three-dimensional knitted fabric, and 75% strain compressive strength of the three-dimensional structure knitted fabric obtained by such heat processing. It is a graph which shows the relationship between the heat processing temperature of a three-dimensional knitted fabric, and 75% strain compressive strength of the three-dimensional structure knitted fabric obtained by such heat processing. It is a graph which shows the relationship between the heat processing temperature of a three-dimensional knitted fabric, and 75% strain compressive strength of the three-dimensional structure knitted fabric obtained by such heat processing. It is a schematic diagram which shows the state which put the weight on the test body made from a three-dimensional structure knitting. It is a graph which shows the relationship between the heat processing temperature of a monofilament yarn made from a polyethylene terephthalate, and a thermal contraction rate. It is a graph which shows the relationship between the heat processing temperature of a monofilament yarn made from a polyethylene terephthalate, and a thermal contraction rate. It is a graph which shows the relationship between the heat processing temperature of a three-dimensional knitted fabric, and 75% strain compressive strength of the three-dimensional structure knitted fabric obtained by such heat processing. It is a graph which shows the relationship between the heat processing temperature of a three-dimensional knitted fabric, and 75% strain compressive strength of the three-dimensional structure knitted fabric obtained by such heat processing.

  In this specification, "three-dimensional knitted fabric" refers to a three-dimensional knitted fabric composed of at least three elements of a front surface, a connecting yarn, and a back surface, formed by connecting two knitted fabrics on the front and back sides with a connecting yarn. The “three-dimensional structure knitted fabric” refers to one obtained by subjecting a three-dimensional knitted fabric to heat treatment. The three-dimensional knitted fabric is knitted by a knitting machine having two rows of needle rows, such as a double raschel knitting machine or a double circular knitting machine. In the three-dimensional knitted fabric and the three-dimensional structured knitted fabric, the patterns on the front and back surfaces are not particularly limited. Examples include a honeycomb pattern, a lattice pattern, a circular pattern, an elliptical pattern, and the like.

  In the three-dimensional knitted fabric of the present invention, the material of the connecting yarn is a synthetic fiber having a melting point of 220 to 270 ° C. measured by a differential scanning calorimetry (hereinafter referred to as “DSC method”), and the melting point is 240 to 260. Synthetic fibers that are at 0C are preferred. The reason for using a material having such a melting point is related to the heat treatment temperature, which will be referred to in the description of the method for producing a three-dimensional knitted fabric.

  Examples of synthetic fibers that can be used for the connecting yarns include polyethylene terephthalate fibers, polybutylene terephthalate fibers, polytrimethylene terephthalate fibers, polyethylene naphthalate fibers, polybutylene naphthalate fibers and other aromatic polyester fibers, and various nylons. Polyamide fibers such as polyamide fibers, polyethylene fibers and polypropylene fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, and the like. Such synthetic fibers have a melting point of 220 to 220 as measured by the DSC method. Select one that is 270 ° C. Among these, aromatic polyester fibers and polyamide fibers are preferable, and aromatic polyester fibers are particularly preferable.

  The connecting yarn may be a monofilament yarn or a multifilament yarn, but is preferably a monofilament yarn from the viewpoint of strain compressive strength and resilience. The thickness of the monofilament yarn is preferably 800 to 2,000 denier (888 to 2,220 dtex), and preferably 1,000 to 1,500 denier (1,110 to 1,667 dtex). Is more preferable.

The density of the connecting yarn, whether monofilament yarn or multifilament yarn, is preferably 300 to 600/25 cm ² , and more preferably 400 to 600/25 cm ² .

  The material of the front and back knitted fabrics is a synthetic fiber whose melting point by DSC method is the same as or slightly lower than the melting point of the material of the connecting yarn. More specifically, 0 ° C. ≦ melting point of connecting yarn by DSC method−melting point of front and back knitted fabrics by DSC method <30 ° C. This means that when the three-dimensional knitted fabric is subjected to heat treatment at a temperature depending on the DSC melting point of the connecting yarn, the knitted fabric on the front and back sides may be melted as long as there is little. For example, when the melting point of the front and back knitted fabrics is about 25 ° C. lower than the melting point of the connecting yarn by the DSC method, when the heat treatment is performed at a temperature 20 ° C. lower than the melting point of the connecting yarn material by the DSC method, The knitted fabrics on the front and back sides are slightly melted, but any melting is possible as long as the melting point is within the range of the melting point of the connecting yarn by DSC method-the melting point of the front and back knitted fabrics by DSC method <30 ° C. It is preferable that 0 ° C. ≦ melting point of connecting yarn by DSC method−melting point of front and back knitted fabric by DSC method <20 ° C.

  Examples of synthetic fibers that can be used for the front and back knitted fabrics include polyamide fibers and aromatic polyester fibers.

  The material of the connecting yarn and the material of the front and back knitted fabrics may be the same or different. Here, “the materials are the same” means that the chemical compositions of the polymers constituting the yarn used for preparing the connecting yarn and the knitted fabric are the same. Therefore, for example, even when aromatic polyester is used as the material for both the connecting yarn and the front and back knitted fabrics, a plurality of types of aromatic polyester are known. When different aromatic polyesters are used as the material of the knitted fabric, the material of the connecting yarn and the material of the knitted fabric on the front and back sides are different from each other.

The three-dimensional structure knitted fabric of the present invention has a pressing force (pressed area: when compressed to 75% of the initial thickness) according to JIS K6400-2 E method (ie, compressed to a thickness of 25% of the initial thickness). 314 cm ² ; compression speed: 100 mm / min) of 85 to 150 kgf. The pressing pressure is preferably 90 to 140 kgf.

  Although the manufacturing method of the three-dimensional structure knitted fabric of this invention is not specifically limited, It is preferable to manufacture with the method of this invention characterized by the heat processing temperature of a three-dimensional knitted fabric. That is, a synthetic fiber having a melting point of 220 to 270 ° C. according to the DSC method is selected as the material of the connecting yarn, and a synthetic fiber as a material of the front and back knitted fabrics is 0 ° C. ≦ the melting point of the connecting yarn by the DSC method−the front and back sides A knitted fabric having a melting point <30 ° C. according to the DSC method is selected, a three-dimensional knitted fabric is knitted by a known method, and it is subjected to a heat treatment under specific conditions.

  Specifically, the heat treatment temperature is 20 to 50 ° C. lower than the melting point of the connecting yarn material by the DSC method, and 20 to 40 ° C. lower than the melting point of the connecting yarn material by the DSC method. Preferably, the temperature is 20 to 35 ° C. lower than the melting point of the connecting yarn material by DSC method. Moreover, after satisfying such conditions, the heat treatment temperature is preferably 190 ° C. or higher, more preferably 200 ° C. or higher, even more preferably 210 ° C. or higher, and 220 ° C. or higher. It is particularly preferred. By performing the heat treatment at a temperature higher than that in the prior art, a three-dimensional knitted fabric having excellent sag resistance can be obtained.

  The “heat treatment temperature” is a set temperature of a heat furnace for heat treatment. The heating furnace is filled with air heated to the set temperature, and while the three-dimensional knitted fabric passes through such a heating furnace over several minutes, the temperature of the connecting yarn is also set in the heating furnace. It is considered to be almost the same as the temperature of air.

  Specific examples of the present invention will be described below.

[Example 1] Production of three-dimensional knitted fabric and strain compression strength test (Part 1)
(1) Manufacture of three-dimensional structure knitted fabric (1-1) Material Front and back knitted fabric forming material: Monofilament yarn made of polyethylene terephthalate with a thickness of 500 denier (555 dtex) (manufactured by Hangzhou Riyaku Plastics Co., Ltd. (China))
Linking thread: Monofilament yarn made of polyethylene terephthalate with a thickness of 1,050 denier (1,165 dtex) (manufactured by Hangzhou Rikang Plastics Co., Ltd., China)

(1-2) Measurement of Melting Point Using EXSTAR6000 DSC66220 manufactured by SII Nanotechnology, the melting point of monofilament yarn made of polyethylene terephthalate was measured by DSC method at a heating rate of 10 ° C./min. The melting points of the connecting yarn used in this example and the monofilament yarn made of polyethylene terephthalate used for the front and back knitted fabric forming materials were both 247.9 ° C.

(1-3) Manufacture of a three-dimensional knitted fabric A double raschel machine (double raschel machine HDR 5DPLM manufactured by KARL MAYER) with 9 gauge / 吋, equipped with 7 pieces of saddle, and 20 to 55 mm (variable) between the pots, 48mm, polyethylene terephthalate monofilament yarn is supplied as a connecting yarn (pile yarn) from two cocoons located in the middle, and polyethylene terephthalate is used as the front yarn and back yarn to the heel guide that forms the ground structure of the front and back. Monofilament yarn was fed in each array. The knitting was set to 9.4 course / 2.54 cm, and a three-dimensional knitted fabric having a width of 131 cm was knitted with an 8-course mesh on the front and a 10-course mesh on the back.

(1-4) Manufacture of three-dimensional structured knitted fabric The three-dimensional knitted fabric knitted in (1-3) is refined at 80 ° C and then heat-treated by passing through a heating furnace set at 180 to 220 ° C, resulting in a finished width of 203 cm. (Thickening ratio: 1.55 times), a three-dimensional knitted fabric having a thickness of 30 mm, a property of 9.9 courses / 2.54 cm, and 5.8 wales / 2.54 cm was obtained. The connecting yarn density of this three-dimensional knitted fabric was 457 pieces / 25 cm ² (5 cm × 5 cm).

  The heat treatment machine used was VIC-800 (heat furnace length: 15 m) manufactured by Ichikin Kogyo Co., Ltd. The furnace of this machine consists of five zones, the first zone is the preheating part (set temperature: 150 ° C), the second to fourth zones are the heating parts (set to the desired heating temperature), and the fifth zone Is a cooling section (set temperature: 150 ° C.). The passing speed of the three-dimensional knitted fabric in the furnace was 3.5 m / min, and the time required for passing was 4 minutes and 20 seconds.

(2) Strain compressive strength test (2-1) Preparation of test specimen A test specimen for measurement having a size of 40 cm x 40 cm was cut out from the three-dimensional structure knitted fabric produced in (1).

(2-2) Test method (JIS K6400-2 E method)
(Measurement condition)
Measurement equipment used: AF-200 manufactured by Kobunshi Keiki Co., Ltd.
Measurement area: 314 cm ² (using a circular compression plate with a diameter of 20 cm)
Compression speed: 100mm / min

(Measuring method)
(I) A 5N (Newton) load is applied to the measurement specimen, the thickness at that time is measured, and this is used as the initial thickness.
(Ii) Compress 75% of the initial thickness with a compression plate at a compression rate of 100 mm / min in the approximate center of the measurement specimen (preliminary compression).
(Iii) Immediately after the precompression, the compression plate is returned to the original state at a speed of 100 mm / min.
(Iv) Measurement, that is, compression at a compression speed of 100 mm / min is started with a compression plate, and the load when 75% of the initial thickness is compressed is measured.

(2-3) Results The pressing pressure (75% strain compressive strength) when 75% of the initial thickness was compressed was as shown in Table 1 and FIG. That is, when heat treatment is performed at a temperature equal to or higher than “melting point of DSC method of connected yarn—about 40 ° C.”, the 75% strain compressive strength increases, and the heat treatment temperature is “melting point of DSC method of connected yarn—about 35 ° C.” or higher. The 75% strain compressive strength was further increased at a temperature of 75 ° C., and the 75% strain compressive strength was significantly increased when the heat treatment temperature was not lower than “melting point of DSC method of connected yarn—about 30 ° C.” or higher.

[Example 2] Production of three-dimensional knitted fabric and strain compression strength test (Part 2)
The same as Example 1 except that monofilament yarn made of polyethylene terephthalate (melting point by DSC method: 247.9 ° C.) having a thickness of 900 denier (999 dtex) was used as the connecting yarn, and the space between the hooks was 50 mm. A three-dimensional knitted fabric was knitted by the method and conditions.

Moreover, it heat-processed by the method and conditions similar to Example 1 except having set the finishing width to 204 cm, and obtained the three-dimensional structure knitted fabric. The connecting yarn density of this three-dimensional knitted fabric was 457 pieces / 25 cm ² (5 cm × 5 cm).

  A strain compression strength test was conducted in the same manner as in Example 1.

  The results of the strain compression strength test are shown in Table 2 and FIG. As is clear from these results, when heat treatment is performed at a temperature equal to or higher than “melting point of DSC method of connecting yarn—about 40 ° C.”, the 75% strain compressive strength increases, and the heat treatment temperature becomes “melting point of DSC method of connecting yarn— When the temperature is about 35 ° C. or higher, the 75% strain compressive strength is higher, and when the heat treatment temperature is higher than the melting point of the connecting yarn by DSC method—about 30 ° C., the 75% strain compressive strength is further increased. .

[Example 3] Production of three-dimensional knitted fabric and strain compressive strength test (Part 3)
As the connecting yarn, a monofilament yarn made of polyethylene terephthalate (melting point by DSC method: 247.9 ° C.) with a thickness of 2,000 denier (2,220 dtex) is used, the distance between the hooks is 46 mm, and the driving is 9.14 courses A three-dimensional knitted fabric was knitted using the same method and conditions as in Example 1 except that it was set to /2.54 cm.

The obtained three-dimensional knitted fabric was heat-treated by the same method and conditions as in Example 1 to obtain a three-dimensional structured knitted fabric. The connecting yarn density of this three-dimensional knitted fabric was 427 pieces / 25 cm ² (5 cm × 5 cm).

  A strain compression strength test was conducted in the same manner as in Example 1.

  The results of the strain compression strength test are shown in Table 3 and FIG. As is clear from these results, when heat treatment is performed at a temperature equal to or higher than “melting point of DSC method of connecting yarn—about 40 ° C.”, the 75% strain compressive strength increases, and the heat treatment temperature becomes “melting point of DSC method of connecting yarn— When the temperature is about 35 ° C. or higher, the 75% strain compressive strength is further increased, and when the heat treatment temperature is equal to or higher than the “melting point of DSC method of connected yarn—about 30 ° C.” or higher, the 75% strain compressive strength is significantly increased. .

  Further, from the results of Examples 1 to 3, the 75% strain compressive strength when the heat treatment is performed at a temperature equal to or lower than “melting point of DSC method of the connecting yarn−about 50 ° C.” is not limited even if the thickness of the connecting yarn is changed. Although the values were almost the same, the 75% strain compressive strength when the heat treatment was performed at a temperature equal to or higher than “melting point of DSC method of connecting yarn—about 40 ° C.” was larger as the connecting yarn was thicker.

[Example 4] Sinking of a three-dimensional knitted fabric (part 1)
A three-dimensional knitted fabric was produced in the same manner as in Example 1, except that the heat treatment temperature was 210 ° C. The 75% strain compressive strength of this three-dimensional knitted fabric was 95.8 kgf / 314 cm ² .

  A test specimen for measurement having a size of 100 cm × 200 cm was cut out from the three-dimensional knitted fabric. The test body was placed in a room at room temperature of 25 ° C., and a male subject (47 years old) having a height of 182 cm and a weight of 79 kg lay in a supine position. When the presence or absence of body depression was observed from the right side of the subject, no body depression was observed.

[Example 5] Sinking of a three-dimensional knitted fabric (part 2)
Similar to Example 1, except that the heat treatment temperature was 180 ° C. or 210 ° C., a three-dimensional knitted fabric was produced. 75% strain compression strength of these three-dimensional structures knitted fabric, those heat treatment temperature is 180 ° C. was 80.1kgf / 314cm ^2, the heat treatment temperature is those of 210 ° C. was 96.4kgf / 314cm ^2.

  A test specimen for measurement having a size of 40 cm × 40 cm was cut out from these three-dimensional knitted fabric. These test specimens were placed in a room at room temperature of 25 ° C., and a standard weight weighing 20 kg was placed thereon.

  The results are shown in FIG. As apparent from FIG. 4, the weight 3 on the three-dimensional knitted fabric specimen 1a having a heat treatment temperature of 180 ° C. is submerged, but the weight 3 on the three-dimensional knitted specimen 1b having a heat treatment temperature of 210 ° C. is subducted. There wasn't.

[Example 6] Measurement of heat shrinkage rate of monofilament yarn (part 1)
Using a monofilament yarn, the shrinkage (heat shrinkage) of the length by heat treatment was measured.

(1) Measurement material Monofilament yarn of polyethylene terephthalate manufactured by Hangzhou Riyaku Plastics Co., Ltd. (China) Thickness = 1,050 denier (1,165 dtex), melting point by DSC method = 247.9 ° C

(2) Measuring equipment Hot air dryer: Advantech's distribution type high temperature and high pressure decomposition equipment DRM420DA

(3) Measuring method The mono-fragment yarn was accurately cut to a length of 1,000 mm and left in a hot air dryer set at 200 to 240 ° C. for 5 minutes. The mono-fragment yarn was taken out from the hot air dryer and its length was measured. The difference from the original length was expressed as a percentage and used as the heat shrinkage rate. Moreover, the state of the monofilament yarn after the heat treatment was observed on the surface and the cut surface.

(4) Results Table 4 shows the heat shrinkage rate, and FIG. 5 shows the relationship between the heat shrinkage rate and the heat treatment temperature. Moreover, about the state of the monofilament yarn after heat processing, as for the thing heat-processed at 230 degreeC and 240 degreeC, it was a result that a melting phenomenon was observed on the surface and a cut surface.

  From FIG. 5, it was considered that the inflection point at which the heat shrinkage rate greatly changed was about 227 ° C. This temperature is about 21 ° C. lower than the melting point of the monofilament yarn used in this experiment by the DSC method. In consideration of the fact that the melting phenomenon was observed in those heat-treated at 230 ° C. and 240 ° C., when the material is a synthetic resin exhibiting such heat shrinkage behavior, the DSC method of the material of the connecting yarn of the three-dimensional knitted fabric It was considered that heat treatment at a temperature of less than 20 ° C. from the melting point due to the risk of deforming the connecting yarn was not appropriate.

[Example 7] Measurement of thermal shrinkage of monofilament yarn (Part 1)
As the measurement material, except that a thickness of 1,000 denier (1,110 dtex), a polyethylene terephthalate monofilament yarn (manufactured by Takada Kasei Co., Ltd.) having a melting point of 252 ° C. by DSC method was used, in the same manner as in Example 6, The heat shrinkage rate of the mono-fragment yarn was measured.

  The thermal shrinkage rate is shown in Table 5, and the relationship between the thermal shrinkage rate and the heat treatment temperature is shown in FIG. In addition, the state of the monofilament yarn after the heat treatment was a result that a melting phenomenon was observed on the surface and the cut surface when heat treated at 240 ° C.

  From FIG. 6, it was considered that the inflection point at which the heat shrinkage rate changes was about 224 ° C. This temperature is about 28 ° C. lower than the melting point of the monofilament yarn used in this experiment by the DSC method. The polyethylene terephthalate, which is the material of the connecting yarn used in this experiment, has a different heat shrinkage behavior from the polyethylene terephthalate, which is the material of the connecting yarn used in the experiment of Example 6, and the increase in the heat shrinkage rate due to the temperature rise. The curve is gentle. Therefore, even if the heat treatment was performed at a temperature slightly higher than the inflection point of the heat shrinkage rate, it was considered that there was little risk of deforming the connecting yarn. Considering the results of the heat shrinkage rates of Examples 6 and 7 and the fact that the melt phenomenon was observed in Example 7 that was heat-treated at 240 ° C., the heat shrinkage rate should be up to about 18%. It was considered that the risk of deforming the connecting yarn during heat treatment was small. Then, also from Example 7, it was considered that heat treatment at a temperature where the difference between the melting point of the connecting yarn material of the three-dimensional knitted fabric by the DSC method was less than 20 degrees (in this example, 232 ° C. or more) was not appropriate.

[Example 8] Production of three-dimensional knitted fabric and strain compressive strength test (Part 4)
As the connecting yarn, a polyethylene naphthalate monofilament yarn (manufactured by Toray Monofilament Co., Ltd.) having a thickness of 1,000 denier (1,110 dtex) and a melting point of 255 ° C. by DSC method was used, and the heat treatment temperature was 190 to 230 ° C. Except for the above, the knitting of the three-dimensional knitted fabric, the production of the three-dimensional knitted fabric, and the strain compression strength test were performed under the same method and conditions as in Example 1. The connecting yarn density of this three-dimensional knitted fabric was 457 pieces / 25 cm ² (5 cm × 5 cm).

  The results of the strain compression strength test are shown in Table 6 and FIG. As is apparent from these results, when heat treatment is performed at a temperature of “melting point by DSC method of connecting yarn—about 50 ° C.” or higher, the 75% strain compressive strength increases, and the heat treatment temperature becomes “melting point of connecting yarn by DSC method— When the temperature is about 35 ° C. or higher, the 75% strain compressive strength is further increased, and when the heat treatment temperature is equal to or higher than the “melting point of DSC method of connected yarn—about 25 ° C.” or higher, the 75% strain compressive strength is significantly increased. .

[Example 9] Manufacture of three-dimensional knitted fabric and compressive strength test (Part 5)
A three-dimensional knitted fabric was formed under the same method and conditions as in Example 1, except that a nylon 66 monofilament yarn (DSC melting point = 258 ° C.) having a thickness of 1,000 denier (1,110 dtex) was used as the connecting yarn. Knitted. Further, except that the heat treatment temperature was 190 to 230 ° C. and the finished width was 204 cm, heat treatment was carried out under the same method and conditions as in Example 1 to obtain a three-dimensional knitted fabric. The connecting yarn density of this three-dimensional knitted fabric was 457 pieces / 25 cm ² (5 cm × 5 cm).

  A strain compression strength test was conducted in the same manner as in Example 1.

  The results of the strain compression strength test are shown in Table 7 and FIG. As is clear from these, not only when polyester is used as the connecting yarn, but also when nylon is used, when heat treatment is performed at a temperature of “melting point of DSC method of the connecting yarn—about 50 ° C.” or higher. 75% strain compressive strength increases, and when the heat treatment temperature is equal to or higher than “melting point of connected yarn by DSC method—about 40 ° C.”, the 75% strain compressive strength further increases, and the heat treatment temperature becomes “DSC method of connected yarn. At a temperature of “melting point by −30 ° C.” or higher, the 75% strain compressive strength was remarkably increased.

1a, 1b Three-dimensional structure knitted specimen 3 Weight

Claims (7)

A three-dimensional knitted fabric composed of front and back knitted fabrics and connecting yarns connecting them, the connecting yarns are made of synthetic fibers having a melting point of 220 to 270 ° C. by the DSC method, and the front and back knitted fabrics are made of synthetic fibers Yes and 0 ° C. ≦ melting point of DSC method for connecting yarn−melting point of DSC method for front and back knitted fabrics <30 ° C., pressing pressure at 75% compression of three-dimensional knitted fabric by JIS K6400-2 E method (pushing) (Area: 314 cm ² ; compression speed: 100 mm / min) 85 to 150 kgf The three-dimensional knitted fabric according to claim 1, wherein the connecting yarn is a monofilament yarn, the thickness thereof is 800 to 2,000 denier, and the density of the connecting yarn is 300 to 600 pieces / 25 cm ² . The three-dimensional structure knitted fabric according to claim 1 or 2, wherein the materials of the connecting yarn and the knitted fabric on the front and back sides are different. The three-dimensional structure knitted fabric according to claim 1 or 2, wherein the connecting yarn and the material of the knitted fabric on the front and back sides are the same. The three-dimensional structure knitted fabric according to any one of claims 1 to 4, wherein both the connecting yarn and the material of the knitted fabric on the front and back sides are aromatic polyester. The front and back knitted fabrics are made of synthetic fibers having a DSC melting point of 220 to 270 ° C., and the front and back knitted fabrics are made of synthetic fibers and 0 ° C. ≦ the DSC of the connecting yarn. The melting point by the method—The solid knitted fabric having a melting point <30 ° C. by the DSC method of the front and back knitted fabrics is heat-treated in a heat furnace set at a temperature 20 to 50 ° C. lower than the melting point by the DSC method of the connecting yarn material. The method for producing a three-dimensional structure knitted fabric according to any one of claims 1 to 5, wherein The method for producing a three-dimensional knitted fabric according to claim 6, wherein the heat treatment is performed in a heating furnace set to 190 ° C or higher.

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