JP5453134B2 - Reticulate - Google Patents

Description

  The present invention relates to a net having excellent mechanical strength and light weight.

  Conventionally, a net-like body using a belt-like body has been used in applications such as packaging materials, agricultural materials, and civil engineering materials that require strength and the like. As a strip constituting the network, Patent Document 1 includes 20 to 100% by weight of an ethylene / acrylic acid ester / maleic anhydride terpolymer and 80 to 0% by weight of a heat-resistable resin. A composite flat yarn in which a first component forms a surface layer and a back surface layer of a yarn, and a second component made of a thermoplastic resin having a melting point 20 ° C. higher than the first component forms an intermediate layer of the yarn. Has been proposed.

  In order to obtain a high-strength network using the above composite flat yarn, it is conceivable to increase the thickness of the composite flat yarn. However, if the original sheet extruded from the die is thick, In the drawing process for increasing the strength of the composite flat yarn, before the sufficient drawing strength is obtained, the flat yarn may be cut or broken, It is difficult to increase the thickness of the composite flat yarn.

  Therefore, although it can be dealt with by increasing the number of composite flat yarns per unit area in the mesh, the strength of the mesh cannot be sufficiently improved, and the lightness of the mesh Improvements were required from the viewpoint of protecting the global environment, such as increased transportation costs and increased carbon dioxide emissions during transportation and packaging materials.

Japanese Patent Application Laid-Open No. 5-247764

  The present invention provides a network having excellent mechanical strength and light weight.

  The network of the present invention will be described with reference to the drawings. The belt-shaped body constituting the network is composed of a stretched thermoplastic polyester resin sheet produced by drawing and stretching a thermoplastic polyester resin sheet and then uniaxially stretching it. Examples of the thermoplastic polyester-based resin constituting the thermoplastic polyester-based resin sheet used for drawing and drawing are polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyglycolic acid, poly (L- Lactic acid), poly (3-hydroxybutyrate), poly (3-hydroxybutyrate / hydroxyvalerate), poly (ε-caprolactone), polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene succin Nate / lactic acid, polybutylene succinate / carbonate, polybutylene succinate / terephthalate, polybutylene adipate / terephthalate, polytetramethyladipate / terephthalate, polybutylene succin Over DOO / adipate / terephthalate, and the like, preferably superior polyethylene terephthalate heat resistance.

  If the intrinsic viscosity of the thermoplastic polyester resin constituting the thermoplastic polyester resin sheet is too low, it tends to cause drawdown at the time of creating the sheet, and if it is too high, it is difficult to increase the draw ratio of the drawing stretch. Therefore, 0.6 to 1.0 is preferable. In addition, the intrinsic viscosity of the thermoplastic polyester resin constituting the thermoplastic polyester resin sheet is a value measured according to JIS K7367-1.

  Although the thickness of the thermoplastic polyester resin sheet used as a raw fabric is not specifically limited, 0.5-4 mm is preferable. If the thickness of the thermoplastic polyester resin sheet is less than 0.5 mm, the sheet thickness after stretching becomes too thin, and the strength during handling may not be sufficient, and if it exceeds 4 mm, stretching may be difficult. Because there is.

  It is preferable that an amorphous polyester resin sheet in an amorphous state is used as a raw material, and the crystallinity thereof is not particularly limited, but the crystallinity measured by a differential scanning calorimeter is less than 10%. Preferably, less than 5% is more preferable. The degree of crystallinity of the amorphous polyester resin sheet in the amorphous state refers to that measured by the density method.

  If the temperature of the thermoplastic polyester resin sheet during drawing and drawing is low, the drawn thermoplastic polyester resin sheet may be whitened, or it may be too hard to tear and be drawn, so that it is drawn and drawn. It is preferable to preheat in advance (glass transition temperature-20 of the thermoplastic polyester resin constituting the thermoplastic polyester resin sheet) in advance. In addition, the glass transition temperature of the thermoplastic polyester-type resin which comprises the thermoplastic polyester-type resin sheet means what was measured based on JISK7121-1987.

  When the temperature of the pair of drawing rolls during the drawing and drawing is too low, the temperature of the drawn thermoplastic polyester resin sheet is lowered and the drawn thermoplastic polyester resin sheet is whitened. Since the resin temperature rises due to frictional heat of the resin and the molecular orientation is relaxed, (the glass transition temperature of the thermoplastic polyester resin constituting the thermoplastic polyester resin sheet−20) ° C. or more and (thermoplastic polyester) It is preferable that it is less than glass transition temperature +20) degreeC of the thermoplastic polyester-type resin which comprises a resin-based resin sheet.

  Further, when the thermoplastic polyester resin sheet is pulled out, the pair of rolls are rotated so that the opposing surfaces thereof are in the drawing direction, thereby reducing the resistance at the time of drawing and stretching, and the stretched thermoplastic polyester resin sheet. This is preferable because it can suppress the generation of the wave.

  In the present invention, a stretched thermoplastic polyester resin sheet obtained by drawing and stretching a thermoplastic polyester resin sheet is uniaxially stretched in the same direction as the above-described stretching.

  In particular, the polyester resin of the stretched thermoplastic polyester resin sheet that has been drawn and stretched has a highly oriented molecular chain in a state in which isotropic crystallization and orientation due to heat, which is an impediment to stretching, are suppressed. However, since the degree of crystallinity is low, when heated, the orientation is easily relaxed and the mechanical strength is lowered.

  Therefore, the stretched thermoplastic polyester resin sheet is preferably uniaxially stretched at a temperature higher than the temperature of the pair of drawing rolls, so that the degree of crystallinity is increased without relaxation and the orientation is easy even when heated. It is possible to obtain a stretched thermoplastic polyester resin sheet having excellent mechanical strength that is not relaxed.

  As a method for uniaxially stretching the stretched thermoplastic polyester resin sheet, a roll stretching method is suitably used. In the roll stretching method, two pairs of rolls are prepared by arranging a pair of rolls with a predetermined interval, and two sets of rolls are provided with a predetermined interval. The stretched thermoplastic polyester resin sheet is disposed between the roll pairs, and the stretched thermoplastic polyester resin sheet is sandwiched between the rolls of each roll pair, so that the rotation speed of one roll pair and the other roll pair By differentiating the rotation speed and making the rotation speed of the downstream roll pair higher than the rotation speed of the upstream roll pair, a tensile force is applied to the stretched thermoplastic polyester resin sheet in the heated state to generate stretching heat. This is a method of pulling a plastic polyester resin sheet, and can be strongly molecularly oriented only in a uniaxial direction. The speed ratio between the roll pairs is the draw ratio.

  When the temperature of the stretched thermoplastic polyester resin sheet when the stretched thermoplastic polyester resin sheet is uniaxially stretched is low, the required stretch ratio of uniaxial stretching may not be obtained. Since the thermoplastic polyester resin sheet is melted and cut, a differential scanning calorimetric analysis of the thermoplastic polyester resin constituting the amorphous thermoplastic polyester resin sheet is performed at a temperature rising rate of 10 ° C./min. In the differential scanning calorimetry curve obtained by measuring by the above, it is preferably not less than the rising temperature of the crystallization peak temperature of the thermoplastic polyester resin and not more than the rising temperature of the melting peak.

  The rising temperature of the crystallization peak of polyethylene terephthalate is about 120 ° C., and the rising temperature of the melting peak is about 230 ° C. Accordingly, when the stretched polyethylene terephthalate sheet is uniaxially stretched, it is preferably uniaxially stretched at 120 to 230 ° C.

  In the stretched thermoplastic polyester resin sheet, if the total draw ratio of the draw ratio of the draw stretch and the stretch ratio of the uniaxial stretch is low, the mechanical strength of the network is lowered, and if it is high, the strip is stretched in the stretch direction. Therefore, 2.5 to 8 times is preferable.

  The draw ratio of the drawing stretching in the uniaxial stretching direction in the stretched thermoplastic polyester resin sheet is not particularly limited, but if the stretching ratio is low, the mechanical strength of the strip may be reduced, Since a strip | belt body becomes easy to break along an extending | stretching direction, 3-7 times are preferable and 4-6 times are more preferable. In addition, the draw ratio of drawing extending | stretching says what remove | divided the length of the sheet | seat after extending | stretching by the length of the sheet | seat before extending | stretching.

  The stretching ratio of the uniaxial stretching of the stretched thermoplastic polyester resin sheet is not particularly limited. However, when the stretching ratio is low, the mechanical strength of the strip may be reduced. When the stretch ratio is high, the strip is stretched. Since it becomes easy to crack along a direction, 1.01-1.2 times are preferable and 1.03-1.1 times are more preferable.

Moreover, if the degree of crystallinity of the uniaxially stretched stretched thermoplastic polyester resin sheet is low, the mechanical strength of the strip is lowered, and if it is high, the strip is easily broken, so it is limited to 20 to 50%. 30 to 45% is preferable . In addition, the crystallinity degree of the stretched thermoplastic polyester-type resin sheet uniaxially stretched means what was measured by the density method.

  Furthermore, the stretched thermoplastic polyester resin sheet that has been uniaxially stretched is preferably heat-set in order to improve its mechanical strength.

  If the thermosetting temperature of the uniaxially stretched thermoplastic polyester resin sheet is lower than the temperature of the thermoplastic polyester resin sheet during uniaxial stretching (uniaxial stretching temperature), the crystallization of the thermoplastic polyester resin will not proceed. Since the mechanical strength is not improved, the uniaxial stretching temperature or higher is preferable, but the differential scanning calorimetric analysis of the thermoplastic polyester resin constituting the thermoplastic polyester resin sheet as a raw fabric is performed at a temperature rising rate of 10 ° C./min. If the temperature rises above the rise temperature of the melting peak in the differential scanning calorimetry curve obtained by measuring with (1), the thermoplastic polyester resin dissolves and the stretching (orientation) disappears, and the mechanical strength of the stretched thermoplastic polyester resin sheet decreases. Therefore, the thermoplastic resin constituting the thermoplastic polyester resin sheet that is higher than the uniaxial stretching temperature and becomes the original fabric Rising the temperature of the melting peak in the differential scanning calorimetric curve obtained by measuring by differential scanning calorimetry polyester resin at a heating rate of 10 ° C. / min conditions less is more preferable.

  Further, when the stretched thermoplastic polyester resin sheet is heat-set when the stretched thermoplastic polyester resin sheet is uniaxially stretched, the stretched thermoplastic polyester resin sheet is stretched and the stretched thermoplastic polyester resin sheet is stretched. Since the stretched thermoplastic polyester resin sheet shrinks when the resin sheet is free, it is preferable that the stretched thermoplastic polyester resin sheet is fixed so as not to shrink due to heat, although the stretched thermoplastic polyester resin sheet is not loaded. It is preferable that no pressure is applied to the thermoplastic polyester resin sheet. For example, it is preferable to heat-set the stretched thermoplastic polyester resin sheet in a state where both ends of the stretched thermoplastic polyester resin sheet are held with a pinch roll or the like so as not to be loaded. The stretched thermoplastic polyester resin sheet is preferably heated with hot air or a heater.

  The time for heat-setting the stretched thermoplastic polyester resin sheet is not particularly limited, and varies depending on the thickness of the stretched thermoplastic polyester resin sheet and the heat setting temperature, but is preferably 10 seconds to 5 minutes.

  A long belt-like body can be obtained by cutting the stretched thermoplastic polyester resin sheet obtained as described above into a predetermined width, preferably a constant width. In addition, it cut | disconnects so that the length direction of a strip | belt-shaped body and the drawing extending | stretching direction of a stretched thermoplastic polyester-type resin sheet may correspond.

  For example, as shown in FIG. 1 or FIG. 2, the net-like body 1 formed from this strip-like body is a strip-like shape in which a large number of strip-like bodies 1 a, 1 a. A body row 1A and a belt-like body row 1B in which a number of belt-like bodies 1b, 1b,... A plurality of through-holes 1c are provided by integrating the intersecting portions of the strips 1A, 1B of these strips 1A, 1B by a known means such as heat fusion or adhesive, As shown in FIG. 3 or FIG. 4, a strip-shaped body row 1D formed by arranging a large number of strip-shaped bodies 1d, 1d... The two strips 1A and 1B forming the mesh body are overlapped in the oblique direction, the strip 1a (1b) of the strip 1A (1B), and the strip 1d of the strip 1D. Intersection with Mention may be made of an adhesive or a mesh-like body obtained by forming so as to provide a large number of holes 1c to be integrated by heat fusion.

  Further, in addition to the mesh body 1, a mesh body 2 as shown in FIG. Specifically, the net 2 includes a wide net 2A formed by arranging a large number of wide nets 2a, 2a,... At predetermined intervals, and a wide net 2a adjacent to each other. A direction in which a plurality of narrow-width net portions 2b, 2b..., Which are connected to each other in a slanted manner with respect to the wide-width net portions 2a, 2a, intersect the wide-width net portions 2a, 2a. It is composed of a narrow-width mesh portion row 2B arranged in parallel at predetermined intervals (in the length direction of the wide-width mesh portion 2a), and is passed by a portion surrounded by the thick-width mesh portion 2a and the narrow-width mesh portion 2b. Two nets formed with holes 2C are a first net 21 and a second net 22, and the first and second nets 21 and 22 are connected to each other with their wide webs 2a and 2a. Stacked and integrated in an orthogonal or skewed state.

  As shown in FIG. 6 and FIG. 7, as the method for manufacturing the mesh body 2, two stretched thermoplastic polyester resin sheets 4 and 4 manufactured as described above are prepared, and each stretched thermoplastic polyester is prepared. ... a plurality of slits 4a, 4a ... of a certain length in the resin-based resin sheet 4, the length direction of which coincides with the drawing and drawing direction, and the slits 4a and 4a adjacent to each other in the drawing and drawing direction partially overlap each other. The slit rows 4A are formed in a state, and the slit rows 4A are formed at predetermined intervals in a direction orthogonal to the extending direction. Note that the slits 4a, 4a, and the like, when focusing on one slit 4a, are a slit 4a 'overlapping on one end side of the slit 4a and a slit 4a "overlapping on the other end side of the slit 4a. Are formed to be opposite to each other across the slit 4a.

  Next, each of the stretched thermoplastic polyester resin sheets 4 is pulled in a direction (width direction) orthogonal to the stretch direction to expand the slits 4a, 4a,. The first and second reticulate bodies 21 and 22 are formed with the thick film portion 2a as the film portion and the thin mesh portion 2b as the film portion between the slits 4a and 4a. The first and second reticulate bodies 21 and 22 are overlapped with each other at an arbitrary position through heat fusion or an adhesive. The net-like body 2 can be manufactured by stacking and integrating.

  Further, as shown in FIG. 8, the net-like body 3 is plain-woven with the band-like body as warps 31 and wefts 32, and the intersections of the warps 31 and the wefts 32 are integrated by an adhesive or heat fusion. FIG. 9 shows a mesh body in which a large number of through holes 33, 33... Are provided by gaps surrounded by the warp 31 and the weft 32, and one surface of the mesh body thus obtained. Thus, in the direction oblique to the warp 31 and the weft 32 of the mesh-like body, the strip-like body row 34 formed by arranging a large number of belt-like bodies 34a, 34a,. 31 and a weft 32 and a net-like body provided with a large number of through holes formed by integrating the intersecting portions of the belt-like bodies 34a, 34a... Is mentioned.

  The net-like body of the present invention is formed from a stretched thermoplastic polyester-based resin sheet and has excellent mechanical strength. Therefore, the number of the belt-like bodies per unit area is increased. It has sufficient mechanical strength without causing it, and even if the thickness of the strip is reduced, sufficient mechanical strength can be maintained. Therefore, the net-like body of the present invention has excellent mechanical strength and light weight, and in addition to uses such as packaging materials, agricultural materials, and civil engineering materials, it is laminated and integrated with a synthetic resin sheet to form a composite sheet. Then, it can be developed for use in the outer panel of an automobile by forming it into a desired shape.

It is the top view which showed the net-like body of this invention. It is the top view which showed another example of the mesh body of this invention. It is the top view which showed another example of the mesh body of this invention. It is the top view which showed another example of the mesh body of this invention. It is the top view which showed another example of the mesh body of this invention. It is a disassembled perspective view of the mesh body of FIG. It is the perspective view which showed the extending | stretching thermoplastic polyester-type resin sheet used as the raw material of the mesh body of FIG. It is the top view which showed another example of the mesh body of this invention. It is the top view which showed another example of the mesh body of this invention.

  Next, examples of the present invention will be described, but the present invention is not limited to the following examples.

Example 1
Polyethylene terephthalate (trade name “NEH2070” manufactured by Unitika Ltd., intrinsic viscosity: 0.88) is supplied to an extruder, melted and kneaded, extruded from a T-die, and 2 mm thick and 600 mm wide polyethylene terephthalate in an amorphous state. A sheet was obtained. The crystallinity of the polyethylene terephthalate sheet was 2.5%.

  Polyethylene terephthalate has a glass transition temperature of 76.7 ° C., and a polyethylene terephthalate crystallization peak in a differential scanning calorimetry curve obtained by measuring polyethylene terephthalate by differential scanning calorimetry at a heating rate of 10 ° C./min. The rising temperature was 139.8 ° C., and the rising temperature of the melting peak was 234 ° C.

  A pair of drawing rolls having a diameter of 500 mm was prepared, and the drawing rolls were arranged so that the distance (gap) between the opposing surfaces was 0.7 mm. Then, after blowing warm air to the polyethylene terephthalate sheet A and preheating it to 60 ° C., the polyethylene terephthalate sheet A is passed through a drawing roll held at 65 ° C. and drawn at a speed of 6 m / min to perform drawing stretching. A stretched polyethylene terephthalate sheet was obtained. The stretch ratio of the stretched polyethylene terephthalate sheet was 5.5 times. The drawing rolls were rotated at a rotational speed of 1.32 m / min so that the opposing surfaces of these drawing rolls were in the drawing direction.

  Next, in the hot air tank maintained at 190 ° C., two pairs of rolls are prepared by arranging a pair of rolls vertically with a gap of 0.5 mm. The stretched polyethylene terephthalate sheet is placed between the two pairs of rolls, and the stretched thermoplastic polyester resin sheet is sandwiched between the rolls of each roll pair, and the upstream (inlet) side Pulling out the stretched polyethylene terephthalate sheet by applying a tensile force to the stretched polyethylene terephthalate sheet in a heated state with a rotational speed of the roll pair of 6 m / min and a rotation speed of the roll pair on the downstream (exit) side of 6.3 m / min. Uniaxial stretching was performed in the same direction as stretching. The crystallinity of the uniaxially stretched polyethylene terephthalate sheet was 37%.

  The uniaxially stretched stretched polyethylene terephthalate sheet was cut every 1.5 mm in the width direction to obtain long strips. In addition, it cut | disconnected so that the length direction of a strip | belt-shaped body and the drawing extending | stretching direction of a stretched polyethylene ethephtalate sheet might correspond.

  And, using the band-like body, a plurality of belt-like bodies 1a, 1a,... Are arranged in parallel every 10 mm, and the band-like body 1a of the band-like body row 1A is at an angle of 45 °. .. In both the belt-like body row 1B formed by stacking a plurality of belt-like bodies 1b, 1b... In parallel every 10 mm and the belt-like bodies 1a, 1b of the belt-like body rows 1A, 1B. It is composed of a belt-like body row 1D which is obliquely crossed at an angle of 45 ° and is laminated on the belt-like body 1b of the belt-like body row 1B and a plurality of belt-like bodies 1d, 1d. A plurality of through holes 1c are formed by laminating and integrating each of the intersecting portions of the strips 1a, 1b, and 1d of the strips 1A, 1B, and 1D with a water-dispersed polyester resin adhesive. The network 1 shown in FIG.

1A strip
1B strip
1D strip
1a Band
1b Band
1c through hole
1d Band 1 Net
2A Thick web section
2B Narrow line section
2C through hole
2a Thick web
2b Narrow web part 2 Net body 3 Net body
4A slit row
4a, 4a ', 4a "slit 4 stretched thermoplastic polyester resin sheet
21 First network
22 Second mesh
31 Warp
32 Weft
33 through holes
34 Bands
34a Band

Claims (3)

From a drawn thermoplastic polyester resin sheet obtained by drawing a thermoplastic polyester resin sheet through a pair of drawing rolls and then uniaxially drawing in the drawing drawing direction and having a crystallinity of 20 to 50% A plurality of strips arranged in parallel at predetermined intervals, and a strip array formed by arranging a number of strips in parallel in a direction intersecting the strips of the strip A net-like body comprising a plurality of through holes provided by integrating the intersecting portions of the belt-like bodies of these belt-like body rows. A wide-width mesh portion row in which a large number of wide-width mesh portions are arranged in parallel at predetermined intervals and a thin-width mesh portion that is connected to each other so as to be inclined with respect to the wide-width mesh portion. A narrow-width-mesh portion row formed by arranging a large number of width-mesh portions at predetermined intervals, and a through-hole is formed by a portion surrounded by the wide-width mesh portion and the narrow-width mesh portion. The first and second nets are laminated and integrated in a state in which the wide webs cross each other, and the first and second nets are formed of a thermoplastic polyester resin sheet between a pair of drawing rolls. The drawn thermoplastic polyester resin sheet, which is obtained by uniaxially stretching in the drawing and drawing direction after being drawn and drawn through, and has a crystallinity of 20 to 50%, has a long slit in the drawing and drawing direction. It is characterized by being expanded by pulling in a direction perpendicular to the stretching direction. The mesh-like body. From a drawn thermoplastic polyester resin sheet obtained by drawing a thermoplastic polyester resin sheet through a pair of drawing rolls and then uniaxially drawing in the drawing drawing direction and having a crystallinity of 20 to 50% A net-like body in which a strip-like body is woven as warps and wefts, and a number of through holes are formed between the belt-like bodies.

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