Hat brim interlining

Abstract

To provide a lightweight hat brim core material having excellent shape retention in MD, TD and any directions, and excellent mechanical strength such as tensile strength and flexural modulus.SOLUTION: There is provided a laminated molded product in which a non-foamed olefin resin layer is laminated on both sides of an olefin resin foam layer with an expansion ratio of 10 times or less and a surface sheet is laminated on both sides of a central material. The surface sheet comprises at least two layers of shape-retaining sheet, and the shape-retaining sheet is a stretched olefin resin sheet, which is bent at 180 degrees in a direction (TD direction) perpendicular to a stretching direction (MD direction), held for 1 minute and then released, with 20 degrees or less of a bending return angle after elapse of 5 minutes, and shape-retaining sheets that are stacked next to each other have different stretching directions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a core material for a hat brim, which is made of a polyolefin resin, is lightweight, and has excellent mechanical strength and shape retention. [Background technology]

[0002] Traditionally, hats have been made from cloth, with the brim made by layering and sewing together multiple layers of cloth. However, when it rains, cloth gets wet and absorbs the rainwater, becoming heavy and deforming, so recently hats made from synthetic resin or hats with only the brim made from synthetic resin have come to be used.

[0003] For example, proposed are a cap in which the brim core is made of a low-expansion PE plate, and the brim is "formed into a curved shape by heating and pressing, and then 'shape-retained' by rapid cooling" (see, for example, Patent Document 1), and a "cap brim core material in which synthetic resin sheets that have shape-retaining properties in one axial direction are laminated and bonded together so that the axial directions of adjacent synthetic resin sheets form a predetermined angle" (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-218120 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-144198

[0005] However, the eaves of the cap described in Patent Document 1 are simply hot-pressed and rapidly cooled, so they have little shape retention, making it difficult for users to give them the shape they want. In addition, they have the disadvantage of requiring press processing to create a curved shape, which increases processing costs.

[0006] Furthermore, the core material for hat brims described in Patent Document 2 has excellent shape retention, but has the drawback of being relatively low in mechanical strength such as tensile strength and flexural modulus, and the sheet is dense and heavy. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above problems, an object of the present invention is to provide a core material for a hat brim which has excellent shape retention in any direction, is lightweight, and has excellent mechanical strength such as tensile strength and flexural modulus. [Means for solving the problem]

[0008] That is, the present invention provides: [1] A core material for a hat brim, characterized in that it is a laminated molded article in which a core material has an olefin-based resin foam layer with an expansion ratio of 10 times or less, on both sides of which unfoamed olefin-based resin layers are laminated, and surface sheets are laminated on both sides of the core material, the surface sheets being made of at least two layers of shape-retaining sheets, the shape-retaining sheets being stretched olefin-based resin sheets, which are folded 180 degrees in a direction (TD direction) perpendicular to the stretching direction (MD direction), held for one minute, and then released, and the return angle after 5 minutes from the release is 20 degrees or less, and the stretching directions of adjacent laminated shape-retaining sheets are different. [2] The core material for a hat brim according to [1] above, characterized in that the stretching directions of adjacently laminated shape-retaining sheets are orthogonal to each other. [3] The olefin resin has a weight average molecular weight of 100,000 to 500,000 and a density of 0.945 to 0.965 g / cm 3 The core material for a hat brim according to the above [1] or [2], characterized in that it is a high-density polyethylene resin. [4] A core material for a hat brim according to any one of the above [1] to [3], characterized in that when the laminated molded body is bent at 180 degrees in a direction (TD direction) perpendicular to the stretching direction (MD direction) of any one of the shape-retaining sheets and held for 1 minute, and then released, the unbent angle 5 minutes after release is 25 degrees or less. [5] The core material for a hat brim according to any one of [1] to [4] above, characterized in that the specific gravity is 0.83 to 0.92, and [6] A core material for a hat brim according to any one of the above [1] to [5], characterized in that the tensile strength is 100 to 200 MPa, and the bending modulus in the direction perpendicular to the stretching direction (MD direction) of any shape-retaining sheet (TD direction) is 3500 to 4500 MPa. Regarding. [Effects of the Invention]

[0009] The structure of the core material for the brim of the hat of the present invention is as described above, and is a laminated molded body made of an olefin-based resin, which has excellent shape retention in any direction, is lightweight, and has excellent mechanical strength such as tensile strength and flexural modulus. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an example of a core material for a brim of a hat according to the present invention. [Figure 2] FIG. 1A is a plan view showing an example of a shape-retaining sheet of the present invention, and FIGS. 1B and 1C are side views showing a method for measuring a 180-degree bending return angle (TD bending). DETAILED DESCRIPTION OF THE INVENTION

[0011] The core material for the brim of a hat of the present invention is a laminated molded product in which a core material has an olefin-based resin foam layer with an expansion ratio of 10 times or less, on both sides of which unfoamed olefin-based resin layers are laminated, and surface sheets are laminated on both sides of the core material, and the surface sheets consist of at least two layers of shape-retaining sheets, and the shape-retaining sheets are stretched olefin-based resin sheets that are bent 180 degrees in a direction perpendicular to the stretching direction (MD direction) (TD direction), held for one minute, and then released, and have a return angle of 20 degrees or less 5 minutes after release, and the stretching directions of adjacent laminated shape-retaining sheets are different.

[0012] Next, the description will be made with reference to the drawings. Fig. 1 is a cross-sectional view showing an example of a core material for a hat brim of the present invention. In the figure, 1 is a core material, and 2, 2 are surface sheets laminated on both sides of the core material 1. The core material 1 has an olefin-based resin foam layer 11 with an expansion ratio of 10 times or less, and unfoamed olefin-based resin layers 12, 12 laminated on both sides of the foamed layer. The surface sheet 2 is composed of a first shape-retaining sheet 21 and a second shape-retaining sheet 22, which are laminated so that the first shape-retaining sheet 21 and the second shape-retaining sheet 22 are stretched olefin-based resin sheets. The first shape-retaining sheet 21 and the second shape-retaining sheet 22 are stretched olefin-based resin sheets that have shape retention properties such that when they are bent 180 degrees in a direction (TD direction) perpendicular to the stretching direction (MD direction), held for one minute, and then released, their return angle is 20 degrees or less 5 minutes after release.

[0013] As the polyolefin resin, any olefin resin having film-forming ability can be used, and examples thereof include high-density polyethylene resin, medium-density polyethylene resin, low-density polyethylene resin, linear low-density polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-pentene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid ester copolymer, ethylene-vinyl chloride copolymer, ethylene-propylene-butene copolymer, etc.

[0014] The weight-average molecular weight of the polyolefin resin is preferably 100,000 to 500,000, since if the weight-average molecular weight is less than 100,000, the mechanical strength or creep resistance will decrease, and if it exceeds 500,000, the melt viscosity will increase, the thermal melt moldability will decrease, and it will be difficult to obtain a uniform sheet. In the present invention, the weight-average molecular weight is a value measured by gel permeation chromatography (GPC).

[0015] The polyolefin resin preferably has a melt index (hereinafter, MI) of 0.1 to 20 (g / 10 min), which provides excellent film formability, and more preferably 0.2 to 10 (g / 10 min). MI is an index representing the melt viscosity of a thermoplastic resin as specified in JIS K 7210.

[0016] Among the above polyolefin resins, the one with high mechanical strength and density of 0.945 to 0.965 g / cm 3 The high density polyethylene resin is preferably a high density polyethylene resin polymerized by a medium to low pressure method and has a density of 0.945 to 0.965 g / cm. 3 It is a polyethylene resin, and may be copolymerized with a small amount of α-olefin such as propylene, butene-1, pentene-1, hexene-1, or octene-1.

[0017] Furthermore, although the polyolefin resins constituting each layer may be different, it is preferable that they be made of the same type of polyolefin resin, since the adhesiveness of each layer will be excellent if the polyolefin resins are the same type, and the mechanical strength of the resulting hat brim core will be improved.

[0018] If necessary, a heat stabilizer, a heat resistance improver, a light stabilizer, an ultraviolet absorber, an antioxidant, an antistatic agent, an impact modifier, an anti-fogging agent, a flame retardant, a colorant, etc. may be added to the polyolefin resin.

[0019] If the expansion ratio of the olefin-based resin foam layer 11 of the core material 1 is too low, weight reduction cannot be achieved, and conversely, if it is too high, mechanical strength decreases, so it is 10 times or less, preferably 6 times or less, and more preferably 1.5 to 3 times.

[0020] The unfoamed olefin-based resin layer 12 of the core material 1 is laminated on the olefin-based resin foam layer 11 and is a layer that imparts mechanical strength to the core material 1, and is preferably laminated on both sides of the olefin-based resin foam layer 11 and firmly adhered thereto.

[0021] The specific gravity and thickness of the core material 1 may be determined appropriately depending on the application and required physical properties, but generally, the specific gravity is 0.65 to 0.85 and the thickness is 0.2 to 5 mm, preferably 0.4 to 1 mm. The thicknesses of the unfoamed olefin resin layers 12, 12 laminated on both sides are preferably approximately the same to prevent uneven distribution of mechanical strength, and the thickness ratio of the unfoamed olefin resin layer 12:the foamed olefin resin layer 11:the unfoamed olefin resin layer 12 is preferably 1:1 to 3:1, more preferably 1:1.5 to 2.5:1.

[0022] The shape-retaining sheet is a stretched olefin-based resin sheet having shape-retaining properties, and its shape-retaining properties are such that when the sheet is bent 180 degrees in the direction (TD) perpendicular to the stretching direction (MD), held for one minute, and then released, the sheet has a return angle (hereinafter referred to as "180-degree return angle") of 20 degrees or less 5 minutes after release. Shape-retaining properties are the property of maintaining a deformed shape as is, so the smaller the return angle, the better the shape-retaining properties. The 180-degree return angle is 20 degrees or less, preferably 15 degrees or less, and more preferably 12 degrees or less.

[0023] Next, a method for measuring the "180-degree bend return angle" will be described with reference to the drawings. Fig. 2(A) is a plan view showing an example of the shape-retaining sheet of the present invention, and (B) and (C) are side views showing a method for measuring the "180-degree bend return angle." In the figure, 23 is a shape-retaining sheet, stretched in the direction of arrow X. That is, the X direction is the stretching direction, which is also the MD direction. The direction of arrow Y is the direction (TD direction) perpendicular to the stretching direction (MD direction).

[0024] To measure the "180-degree bend return angle," first fold the flat shape-retaining sheet 23 shown in Figure 2(A) in half along dotted line 24, i.e., in the direction (TD) perpendicular to the stretching direction (MD), and then overlap the two layers (folded 180 degrees) as shown in Figure 2(B). When the overlapped shape-retaining sheet 23 is held for one minute and then released, the overlapped shape-retaining sheet 23 acts to return to its original shape, as shown in Figure 2(C), and the angle θ formed by the two layers (the angle at which the 180-degree bent molded body returns to its original shape) is measured five minutes after release. This angle θ is the "180-degree bend return angle."

[0025] Furthermore, when the film is bent at 90 degrees in the direction perpendicular to the stretching direction (MD direction) (TD direction), held for 1 minute, and then released, the bending return angle 5 minutes after release (hereinafter referred to as "90-degree bending return angle") is preferably 20 degrees or less, more preferably 15 degrees or less, and even more preferably 12 degrees or less.

[0026] The method for measuring the "90-degree bend return angle" is the same as the method for measuring the "180-degree bend return angle," except that the bending angle is 90 degrees. Specifically, the "90-degree bend return angle (TD bending)" is measured by bending a flat shape-retaining material at 90 degrees in the direction perpendicular (TD) to the stretching direction (MD), holding that shape for one minute, and then releasing it. The shape-retaining sheet acts to return to its original shape, so the angle formed by the folded shape-retaining sheet five minutes after release is measured. The angle obtained by subtracting 90 degrees from the measured angle (the angle at which the shape-retaining sheet bent 90 degrees returns to its original shape) is the "90-degree bend return angle."

[0027] The shape-retaining sheet preferably has a high mechanical strength, and the tensile modulus in the stretching direction (MD) is preferably 10 to 30 GPa, and the tensile strength is preferably 300 to 700 MPa. In the present invention, the tensile modulus and tensile strength are values ​​measured in accordance with JIS K 7127.

[0028] The thickness of the shape-retaining sheet is not particularly limited, but is generally 0.1 to 1 mm, since a thicker sheet becomes heavier and makes it difficult to manufacture a sheet with shape-retaining properties.

[0029] Furthermore, in order to impart flexibility, suppleness, etc. to the shape-retaining sheet made of high-density polyethylene resin and make it less susceptible to longitudinal tearing, one or more resins selected from the group consisting of α-olefin copolymers, linear low-density polyethylenes, olefin-based thermoplastic elastomers, and metallocene-based polypropylene resins may be added to the high-density polyethylene resin. However, if the amount added is too large, the bending angle increases and shape retention decreases, so the amount of resin added is preferably 7 parts by weight or less per 100 parts by weight of high-density polyethylene resin.

[0030] The topsheet 2 is made of at least two layers of shape-retaining sheets, and the stretching directions of adjacent layered shape-retaining sheets are different. It is preferable that the stretching directions of the shape-retaining sheets are uniformly arranged in the topsheet to prevent uneven distribution of mechanical strength.

[0031] That is, for example, when the topsheet is made up of two layers, a first shape-retaining sheet and a second shape-retaining sheet, it is preferable that the stretching directions of the first shape-retaining sheet and the second shape-retaining sheet are arranged so that they are orthogonal.Also, when the topsheet is made up of three layers, a first shape-retaining sheet, a second shape-retaining sheet, and a third shape-retaining sheet, it is preferable that the stretching directions of each shape-retaining sheet are arranged so that they differ by 60 degrees.Furthermore, when the topsheet is made up of four layers, a first shape-retaining sheet, a second shape-retaining sheet, a third shape-retaining sheet, and a fourth shape-retaining sheet, it is preferable that the stretching directions of adjacent shape-retaining sheets are arranged so that they are orthogonal to each other or differ by 45 degrees.

[0032] Furthermore, the topsheet 2 may be made up of at least two layers of shape-retaining sheets, but it is not practical to stack a large number of shape-retaining sheets, and generally, it is preferable to stack two to four layers of shape-retaining sheets.

[0033] The thickness of the topsheet 2 is not particularly limited, but is generally 0.2 to 2 mm, since a thicker topsheet would be heavier and would require laminating multiple shape-retaining sheets, making production difficult.

[0034] The hat brim core of the present invention is configured as a laminated molded product as described above, and is preferably lightweight and excellent in mechanical strength and shape retention, with a specific gravity of preferably 0.83 to 0.92, more preferably 0.85 to 0.92, a tensile strength of 100 to 200 MPa, and a flexural modulus of 3500 to 4500 MPa in the direction perpendicular to the stretching direction (MD) of any shape-retaining sheet constituting the laminated molded product. The flexural modulus is a value measured in accordance with JIS K 7171 at a test speed of 5 mm / min.

[0035] Furthermore, it is preferable that the shape retention of the hat brim core material (laminate molded product) is approximately the same in any direction, and the 180-degree bend return angle and 90-degree bend return angle are preferably 30 degrees or less, more preferably 25 degrees or less. In particular, when the hat brim core material (laminate molded product) is bent 180 degrees in the direction perpendicular (TD direction) to the stretching direction (MD direction) of one of the shape-retaining sheets and held for one minute, and then released, it is preferable that the bend return angle 5 minutes after release is 25 degrees or less.

[0036] The thickness of the core material for the brim of the hat is not particularly limited and may be determined appropriately depending on the intended use, but is generally 0.5 to 20 mm, preferably 1 to 10 mm.

[0037] The method for producing the core material is not particularly limited, and any conventionally known production method may be used. For example, an olefin-based resin foam sheet with an expansion ratio of 10 times or less and an unfoamed olefin-based resin sheet may be produced in advance, and the unfoamed olefin-based resin sheets may be laminated on both sides of the olefin-based resin foam sheet, followed by bonding with an adhesive or by heat fusion. However, since it is preferable that the olefin-based resin foam layer and the unfoamed olefin-based resin layer are uniformly and firmly bonded, a three-layer extrusion method is preferred.

[0038] The three-layer extrusion method is a conventionally known method for producing a laminated sheet in which two types of resin compositions are simultaneously extruded into sheets from different extruders and laminated to produce a three-layer sheet, and examples of such methods include extrusion methods using a multi-coat die, a feed block, etc. In producing the core material, an olefin resin and a foamable olefin resin composition are simultaneously extruded, and the foamable olefin resin composition is foamed to obtain an olefin resin foamed sheet, and at the same time, unfoamed olefin resin sheets formed by extrusion molding an olefin resin on both sides of the olefin resin foamed sheet are laminated in a molten state in a multi-coat die, a feed block, etc. to produce a three-layer sheet.

[0039] The foaming method is not particularly limited, and examples thereof include chemical foaming and gas foaming. Any conventionally known foamable olefin-based resin composition can be used as the foamable olefin-based resin composition used in foaming, and the foamable olefin-based resin composition comprises an olefin-based resin and a foaming agent. Examples of the foaming agent include a thermal decomposition type chemical foaming agent, carbon dioxide gas, and nitrogen gas.

[0040] Examples of thermal decomposition type chemical foaming agents include sodium bicarbonate, ammonium bicarbonate, sodium borohydride, azodicarboxamide, N,N-dinitrosopentamethylenetetramine, P,P-oxybis(benzenesulfonylhydrazide), azobisisobutyronitrile, and paratoluenesulfonylhydrazide.

[0041] The shape-retaining sheet is made of an oriented olefin-based resin sheet, and the manufacturing method of the olefin-based resin sheet is not particularly limited, and any conventionally known manufacturing method may be adopted, for example, an extrusion method, an inflation method, a casting method, a T-die method, a calendar method, etc.

[0042] The shape-retaining sheet is a sheet obtained by stretching an olefin-based resin sheet, and any conventionally known stretching method may be used as the stretching method, such as rolling, or a method using rolling and uniaxial stretching in combination.

[0043] First, a method for producing a shape-retaining sheet by rolling will be described. Rolling is a method in which the olefin-based resin sheet is fed between a pair of rolling rolls, crushed, and stretched.

[0044] The thickness of the olefin resin sheet before rolling is not particularly limited, but if it is too thick, a large pressure force or take-up force will be required to crush the olefin resin sheet with the rolling rolls, and uniform rolling in the width direction may become difficult due to deflection of the rolling rolls. Conversely, if it is too thin, the thickness of the olefin resin sheet after rolling will be too thin, making uniform rolling difficult and the rolling rolls may come into contact with each other, shortening the life of the rolling rolls, so a thickness of 0.2 to 15.0 mm is preferable.

[0045] If the rolling temperature is too low, uniform rolling is not possible, and if it is too high, melting and cutting occurs, so the roll temperature during rolling is preferably in the range of "melting point -40°C" to the melting point of the olefin resin of the olefin resin sheet to be rolled, and more preferably "melting point -30°C" to "melting point -5°C" of the olefin resin. In the present invention, the melting point refers to the maximum point of the endothermic peak associated with crystal melting, observed when thermal analysis is performed with a differential scanning calorimeter (DSC).

[0046] If the pressure (linear pressure) applied to the olefin-based resin sheet by the rolling roll is too small, it may not be possible to obtain the desired rolling ratio. Conversely, if it is too large, not only will the rolling roll bend, but slippage will easily occur between the rolling roll and the olefin-based resin sheet, making uniform rolling difficult. Therefore, the pressure is preferably 100 MPa to 3000 MPa, and more preferably 300 MPa to 1000 MPa.

[0047] The rolling ratio is preferably 5 times or more, more preferably 7 times or more, and even more preferably 9 times or more, since a rolling ratio of less than 5 times will not be able to provide sufficient shape retention. There is no upper limit to the rolling ratio, but a higher rolling ratio puts more strain on the rolling equipment, so a rolling ratio of 20 times or less is preferred. The rolling ratio is defined as (cross-sectional area of ​​the sheet before rolling) / (cross-sectional area of ​​the sheet after rolling), but since the width of the sheet hardly changes before and after rolling, it may also be (thickness of the sheet before rolling) / (thickness of the sheet after rolling).

[0048] Next, a method for producing a shape-retaining sheet by combining rolling and uniaxial stretching will be described. In this method for producing a shape-retaining sheet, it is preferable to roll an olefin resin sheet and then uniaxially stretch it to a total stretch ratio of 10 to 40 times, and the rolling method is as described above.

[0049] The rolling ratio is preferably 5 times or more, more preferably 7 times or more, because if the rolling ratio is less than 5 times, the effect of suppressing necking during the subsequent uniaxial stretching cannot be obtained, high-ratio uniaxial stretching cannot be performed, or a burden is placed on the uniaxial stretching step. There is no upper limit to the rolling ratio, but a rolling ratio of 11 times or less is preferred, because a higher rolling ratio puts a greater burden on the rolling equipment.

[0050] Any conventionally known method may be used for the uniaxial stretching method, and examples thereof include uniaxial stretching methods such as roll uniaxial stretching and zone uniaxial stretching, in which the film is stretched while being heated with a heater or hot air. For high-stretching, a multistage uniaxial stretching method in which uniaxial stretching is repeated multiple times is preferred. When multistage uniaxial stretching is performed, the number of stretching times is preferably 2 to 20, more preferably 3 to 15, and even more preferably 4 to 10.

[0051] When multistage stretching is performed by the roll uniaxial stretching method, it is desirable to provide a feed pinch roll, a take-up pinch roll, and at least one, preferably a plurality of contact rolls rotating at a constant speed between these rolls. By providing such contact rolls, uniform stretching can be improved, and stable stretching can be performed.

[0052] The contact roll performs uniaxial stretching by applying frictional force to the olefin resin sheet without being pinched. The contact roll may be connected to the payout roll and / or take-up roll by a connecting member consisting of a gear, a chain, a pulley, a belt, or a combination thereof.

[0053] If the uniaxial stretching temperature is too low, the olefin resin sheet cannot be stretched uniformly, and if it is too high, the olefin resin sheet will melt and break. Therefore, the temperature is preferably in the range of "melting point -60°C" to the melting point of the olefin resin of the olefin resin sheet to be stretched, and more preferably "melting point -50°C" to "melting point -5°C" of the olefin resin.

[0054] Since the total stretching ratio is preferably 10 to 40 times, the uniaxial stretching ratio should be determined so that it falls within this range, taking into account the rolling ratio. However, since a small amount of uniaxial stretching does not improve the mechanical strength, the uniaxial stretching ratio is preferably 1.1 times or more, more preferably 1.3 times or more. There is no particular upper limit, but the upper limit is preferably 4 times or less, more preferably 3.0 times or less. The total stretching ratio is the value obtained by multiplying the rolling ratio and the uniaxial stretching ratio.

[0055] To improve the dimensional stability of the shape-retaining sheet obtained by the above-mentioned manufacturing method, the sheet may be annealed at a temperature between "melting point -60°C" and the melting point of the olefin resin. If the annealing temperature is too low, the dimensional stability will not improve and warping will occur after prolonged use, while if the annealing temperature is too high, the olefin resin will melt, losing its orientation and decreasing the tensile modulus, tensile strength, etc., so annealing at a temperature between "melting point -60°C" and the melting point of the olefin resin is preferred.

[0056] Annealing is a heat treatment carried out in a production line, and since the shape-retaining sheet will be stretched if a large tension is applied during annealing, and will shrink if no tension or very little tension is applied, it is preferable to perform annealing in a state where the length of the shape-retaining sheet in the stretching direction does not change substantially, and it is also preferable that no pressure is applied to the shape-retaining sheet. In other words, it is preferable to anneal so that the length of the annealed shape-retaining sheet is 1.0 or less of the length of the shape-retaining sheet before annealing.

[0057] Therefore, when the shape-retaining sheet is continuously annealed while being moved in a heating chamber by rolls such as pinch rolls, it is preferable to set the feed speed ratio of the shape-retaining sheet on the entrance side to the exit side to be 1.0 or less during annealing.

[0058] The heating method for annealing is not particularly limited, and examples thereof include heating with hot air, a heater, a heating plate, warm water, etc. The annealing time is not particularly limited, and varies depending on the width and thickness of the stretched shape-retaining material and the annealing temperature, but is generally preferably 10 seconds or more, more preferably 30 seconds to 60 minutes, and even more preferably 1 to 20 minutes.

[0059] The annealed shape-retaining sheet may be further aged in the temperature range of 40° C. to the melting point of the olefin-based resin. Aging improves the dimensional stability of the annealed shape-retaining sheet.

[0060] Aging is not a continuous process on a production line, but refers to the heat treatment of a shape-retaining sheet once processed into a sheet, roll, etc., by leaving it to rest for a relatively long time (minutes or hours). If the aging temperature is low, it will be the same as leaving it at room temperature, but if it is high, it will cause thermal deformation, so it is in the temperature range of 40°C to the melting point of the olefin resin. A short aging time is not effective, and if it is too long, the effect will not increase, so 12 hours to 7 days is preferable.

[0061] The method for manufacturing the surface sheet by stacking the above-mentioned multiple shape-retaining sheets and the method for stacking the surface sheet on both sides of the core material may be any conventionally known method, such as a method of bonding using an adhesive or pressure-sensitive adhesive and a sheet thereof.

[0062] Furthermore, since the mechanical strength of the hat brim core (laminated molded product) of the present invention is preferably high and not unevenly distributed, it is preferable that the multiple shape-retaining sheets are uniformly and firmly adhered to each other and between the top sheets and the core material. Therefore, it is preferable to laminate hot-melt olefin resin sheets between the multiple shape-retaining sheets and between the top sheets and the core material, and bond them by heating and pressurizing.

[0063] The hot-melt olefin resin sheet is preferably made of an olefin resin having a melting point lower than that of the olefin resin constituting the shape-retaining sheet and the core material, so that the shape-retaining ability of the shape-retaining sheet does not decrease or the core material does not deform when laminated by heating and pressurizing. For example, linear low-density polyethylene resin, ethylene-vinyl acetate copolymer, etc. may be mentioned.

[0064] Therefore, the olefin resin that constitutes the shape-retaining sheet and the core material has a weight-average molecular weight of 100,000 to 500,000 and a density of 0.945 to 0.965 g / cm 3 The olefin resin constituting the hot melt type olefin resin sheet is preferably a linear low density polyethylene resin.

[0065] Alternatively, a hot-melt olefin resin sheet may be bonded to the surface of the shape-retaining sheet or the top sheet in advance. This bonding may be performed by any conventionally known method, for example, Examples of such methods include a method of extrusion coating the surface of a shape-retaining sheet or a top sheet with a molten hot-melt olefin-based resin, and a method of laminating a hot-melt olefin-based resin sheet on the surface of a shape-retaining sheet or a top sheet and then heating and pressurizing the hot-melt olefin-based resin sheet to bond it together.

[0066] Furthermore, when performing the above-mentioned bonding, if multiple narrow shape-retaining sheets are arranged with their stretching directions aligned so that they are the same, and then bonded to the hot-melt olefin-based resin sheet, a wide laminated molded body can be easily produced.

[0067] When manufacturing a core material (laminated molded body) for a hat brim by heating and pressurizing a surface sheet and a core material, the surface sheet and core material laminated with the above-mentioned hot-melt type olefin-based resin sheet may be used, and further, a hot-melt type olefin-based resin sheet may be laminated between the surface sheet and the core material and heated and pressurized.

[0068] Since the methods for producing the core material and shape-retaining sheet of the present invention are as described above, a preferred method for producing the core material (laminated molded product) for a hat brim of the present invention comprises the steps of: extruding an olefin-based resin and a resin composition consisting of an olefin-based resin and a foaming agent using a three-layer extruder to obtain a core material in which unfoamed olefin-based resin layers are laminated on both sides of an olefin-based resin foamed layer with an expansion ratio of 10 times or less; rolling the olefin-based resin sheet, uniaxially stretching it to a total stretch ratio of 10 to 40 times, bending it 180 degrees in the direction perpendicular to the stretching direction (MD direction) (TD direction), holding this for 1 minute, and then releasing it to obtain a shape-retaining sheet having a reversion angle of 20 degrees or less 5 minutes after release; and laminating at least two layers of the obtained shape-retaining sheet on both sides of the obtained core material, each layer having a different stretching direction, and bonding them by heating and pressing.

[0069] The hat brim is formed by covering the hat brim core with a covering material, and the hat is formed by attaching the hat brim to the hat body.

[0070] As the covering material, any known covering material that is used in the manufacture of hats can be used, and examples thereof include cloth, olefin resin sheets, vinyl chloride resin sheets, nonwoven fabrics, etc.

[0071] The method for covering the core material for the brim of the hat with the covering material may be any conventionally known method, and examples thereof include a method in which the core material for the brim of the hat is covered with the covering material and then adhesively bonded with a rubber-based, acrylic-based, urethane-based, silicone-based or other adhesive; a method in which the core material is adhesively bonded with a hot-melt adhesive such as an ethylene-vinyl acetate copolymer or a linear low-density polyethylene resin; and a sewing method.

[0072] The hat body can be any conventionally known hat body used in manufacturing hats, such as hats made from cloth, olefin resin sheets, vinyl chloride resin sheets, nonwoven fabrics, straw, etc.

[0073] The method of attaching the hat brim to the hat body may also be any conventionally known method. For example, the method may be a method of attaching the hat brim to the hat body and using a rubber, acrylic, urethane, or silicone material. Examples of suitable adhesives include adhesive bonding with adhesives of the type such as ethylene-vinyl acetate copolymer and linear low-density polyethylene resin, hot melt adhesives such as ethylene-vinyl acetate copolymer and linear low-density polyethylene resin, and sewing. [Example]

[0074] Next, examples of the present invention will be described, but the present invention is not limited to these examples.

[0075] Example 1 A low-density polyethylene resin ("Suntec LD" manufactured by Asahi Kasei Corporation) was supplied to the two extruders for forming the surface layer of a three-layer co-extruder (manufactured by Hitachi Zosen Corporation), and a high-density polyethylene resin ("Novatec HD" manufactured by Japan Polyethylene Corporation, weight-average molecular weight 330,000, MFR 0.40 g / 10 min, density 0.956 g / cm) was supplied to the extruder for forming the middle layer. 3 A foamable resin composition consisting of 100 parts by weight of propylene glycol acrylate (melting point 133°C) and 0.25 parts by weight of azodicarbonamide was supplied, and each was melt-kneaded at a cylinder temperature of 180 to 230°C, followed by co-extrusion of three layers to obtain a core material with a thickness of 1.0 mm.

[0076] The obtained core material had unfoamed low-density polyethylene resin layers laminated on both sides of a high-density polyethylene resin foam layer, with a thickness ratio of low-density polyethylene resin layer: high-density polyethylene resin foam layer: low-density polyethylene resin layer of approximately 1:2:1. The high-density polyethylene resin foam layer had an expansion ratio of approximately 2 and a specific gravity of 0.7.

[0077] High-density polyethylene resin (Novatec HD manufactured by Japan Polyethylene Corporation, weight-average molecular weight 330,000, MFR 0.40 g / 10 min, density 0.956 g / cm 3 The resin (melting point: 133°C) was fed into a co-rotating twin-screw extruder (manufactured by the Plastics Engineering Research Institute) and melt-kneaded at a resin temperature of 200°C. The melt-kneaded product was then formed into a sheet using a calendar molding machine with the roll temperature controlled at 110°C, yielding a sheet with a thickness of 2.8 mm.

[0078] The obtained sheet was rolled out 10 times using a rolling molding machine (manufactured by Sekisui Machinery Works) heated to 125°C, and then subjected to uniaxial multistage stretching of 1.4 times using a hot air heating type multistage stretching device (manufactured by Kyowa Engineering) heated to 110°C, resulting in a stretched sheet with a total stretching ratio of 14 times and a thickness of 0.20 mm.

[0079] The obtained stretched sheet was fed into a hot air heating bath with a line length of 19.25 m, equipped with a pinch roll and set at 125°C, at an inlet speed of 2.75 m / min, and subjected to primary annealing for 7 minutes at an outlet speed of 2.75 m / min. Secondary annealing was then performed in the same manner to obtain an annealed stretched sheet, which was then fed into a constant temperature bath at 60°C and aged for 24 hours to obtain a shape-retaining sheet.

[0080] The obtained shape-retaining sheet was cut into a width of 10 mm and a length of 15 cm, and fed into a Tensilon universal testing machine (Orientec Co., Ltd., "RTC-1250A" model), and subjected to a tensile test in the stretching direction (MD direction) at a speed of 100 mm / min to measure the tensile modulus, tensile strength, and elongation at break in accordance with JIS K 7127. The tensile modulus was 24 GPa, the tensile strength was 500 MPa, and the elongation at break was 5%.

[0081] The obtained shape-retaining sheet was cut into a piece 10 mm wide and 15 cm long, and the 180-degree bend return angle and the 90-degree bend return angle were measured, finding them to be 7 degrees and 5 degrees, respectively.

[0082] Linear low-density polyethylene resin (Novatec LL manufactured by Japan Polyethylene Corporation, MFR 2.1 g / 10 min, density 0.920 g / cm 3 The resulting mixture (having a melting point of 123°C) was fed into a co-rotating twin-screw kneading extruder (manufactured by the Plastics Engineering Research Institute) and melt-kneaded at a resin temperature of 200°C. The molten mixture was then formed into a sheet using a calendar molding machine with the roll temperature controlled at 110°C, yielding a hot-melt adhesive sheet having a thickness of 0.03 mm.

[0083] The obtained hot melt adhesive sheet was laminated on one side of the obtained shape-retaining sheet and pressed from the hot melt adhesive sheet side at a temperature of 125°C and a pressure of 50 KPa to obtain a multilayer shape-retaining sheet with a 0.23 mm thick hot melt adhesive sheet adhered thereto.

[0084] A laminated sheet was obtained by laminating the first multilayer shape-retaining sheet / hot melt adhesive sheet / second multilayer shape-retaining sheet / hot melt adhesive sheet / core material / hot melt adhesive sheet / third multilayer shape-retaining sheet / hot melt adhesive sheet / fourth multilayer shape-retaining sheet in this order. The first to fourth multilayer shape-retaining sheets were arranged so that the hot melt adhesive sheet was located on the core material side, the stretching directions of the first and fourth multilayer shape-retaining sheets were the same, and the stretching directions of the second and third multilayer shape-retaining sheets were perpendicular to the stretching directions of the first and fourth multilayer shape-retaining sheets.

[0085] The resulting laminated sheet was then fed into a press and bonded under heat and pressure at 125°C and 30 MPa to obtain a hat brim core (laminated molded product) of the present invention. The resulting hat brim core had a thickness of 1.92 mm and a specific gravity of 0.85.

[0086] The resulting hat brim core material was cut into a width of 0 mm and a length of 15 cm and fed into a Tensilon universal testing machine (Orientec Co., Ltd., "RTC-1250A" model). A tensile test was performed in the stretching direction (MD) at a speed of 100 mm / mm in accordance with JIS K 7127 to measure the tensile modulus, tensile strength, and elongation at break. The tensile modulus was 3 GPa, the tensile strength was 120 MPa, and the elongation at break was 9%. The flexural modulus, measured at a test speed of 5 mm / min in accordance with JIS K 7171, was 4000 MPa.

[0087] The obtained hat brim core material was cut into a width of 10 mm and a length of 15 cm along the stretching direction of the shape-retaining sheet, and the 180-degree bend return angle and the 90-degree bend return angle were measured, which were 20 degrees and 30 degrees.Furthermore, the laminated molded product was cut into a width of 10 mm and a length of 15 cm at an angle of 45 degrees to the stretching direction of the shape-retaining sheet, and the 180-degree bend return angle and the 90-degree bend return angle were measured, which were 20 degrees and 30 degrees.

[0088] The resulting core material for the hat brim was fed into a punching machine equipped with a Thomson blade, punched into the shape of a hat brim, and fabric was laminated on both sides of the punched core and sewn together to obtain the hat brim. The hat brim was then sewn to the hat body to obtain the hat. When the resulting hat brim was manually bent in any direction at approximately 30 degrees and approximately 45 degrees, the brim was easily bent and was able to maintain its shape. [Industrial Applicability]

[0089] The core material for hat brims of the present invention has excellent mechanical strength such as tensile strength and flexural modulus, has little directional tendency in shape retention, and has excellent shape retention in any direction.Hat brims manufactured using this core material for hat brims have excellent mechanical strength such as tensile strength and flexural modulus, has little directional tendency in shape retention, and has excellent shape retention in any direction, making the hats suitable for use. [Explanation of symbols]

[0090] 1 Core material 11 Olefin resin foam layer 12 Unfoamed olefin resin layer 2 Surface sheet 21, 22, 23 Shape retention sheet X MD direction (stretching direction) Y TD direction (direction perpendicular to the stretching direction) θ 180 degree bend return angle

Claims

1. Expansion ratio of 10 times or less, weight average molecular weight of 100,000 to 500,000, density of 0.945 to 0.965 g / cm ３ a laminated molding in which surface sheets are laminated on both sides of a core material in which unfoamed polyethylene resin layers that impart mechanical strength to both sides of a foamed polyethylene resin layer made of high-density polyethylene resin, and the surface sheets are made of at least two layers of shape-retaining sheets, and the shape-retaining sheets are stretched olefin resin sheets, which are folded 180 degrees in a direction (TD direction) perpendicular to the stretching direction (MD direction), held for one minute, and then released, and the unbending angle five minutes after release is 20 degrees or less, and the stretching directions of adjacent laminated shape-retaining sheets are different. and the laminated molded body is a core material for a hat brim in which the laminated molded body is folded 180 degrees in a direction (TD direction) perpendicular to the stretching direction (MD direction) of one of the shape-retaining sheets, held for one minute, and then released, and the bending return angle 5 minutes after release is 25 degrees or less. In this core material for a hat brim, hot-melt olefin-based resin sheets having a melting point lower than the melting point of the olefin-based resin constituting the shape-retaining sheets and core material are laminated between the multiple shape-retaining sheets that form the surface sheet and between the surface sheet and core material, and are bonded by heating and pressurizing.

2. 2. The core material for a hat brim according to claim 1, wherein the stretching directions of adjacently stacked shape-retaining sheets are perpendicular to each other.

3. 3. The core material for a hat brim according to claim 1, wherein the thickness ratio of the unfoamed polyethylene resin layer to the foamed polyethylene resin layer to the unfoamed polyethylene resin layer in the core material is 1:1 to 3:

1.

4. 4. The core material for a hat brim according to claim 1, wherein the specific gravity is 0.83 to 0.

92.

5. A core material for a hat brim according to any one of claims 1 to 4, characterized in that the tensile strength is 100 to 200 MPa, and the bending modulus in the direction perpendicular to the stretching direction (MD direction) of any of the shape-retaining sheets (TD direction) is 3500 to 4500 MPa.

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