Extrusion-molded sheet, laminate, and resin composition

Abstract

To provide an extrusion molding sheet which prevents occurrence of draw resonance even when molding speed is increased and the sheet is thinned without causing a molding failure in a filler-containing system, a laminate using the extrusion molding sheet, and a resin composition used for the extrusion molding sheet.SOLUTION: An extrusion molding sheet has a strain hardening index of 0.05-0.4 which is measured under conditions of 230°C and strain speed of 1 sec-1, and 3η+ of 2,000-15,000 which is a value obtained by trebling a complex viscosity measured under conditions of 230°C, a swing angle of 1% and angular frequency of 1 s-1, and contains a filler.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an extrusion-molded sheet, a laminate, and a resin composition. [Background technology]

[0002] Extrusion molding is a known method for molding resin into a sheet. Extrusion molding involves forcing resin out of a mold (die) at the end of an extruder. In addition to methods that extrude a single type of resin, there are also other methods, such as co-extrusion, in which multiple resins are extruded simultaneously, and extrusion lamination, in which resin is extruded onto a substrate and layered. In these extrusion molding methods, the resin extruded from the die is drawn between rolls and molded into a sheet.

[0003] In recent years, environmental issues and cost reductions have led to demands for faster molding speeds and thinner sheets. To achieve thinner sheets, the extrusion speed of the resin from the die must be reduced. Furthermore, increasing the molding speed increases the take-up speed of the resin extruded from the die. In this case, if the extrusion speed is low and the take-up speed is high, a large load is placed on the extruded resin, which can cause unevenness in the resin after extrusion and before take-up, known as draw resonance (surging).

[0004] Slowing the molding speed while balancing the extrusion speed and take-up speed can suppress draw resonance, but this reduces productivity. For this reason, attempts have been made to improve the material. For example, improving the fluidity of the resin or adding low-density polyethylene or long-chain branched polypropylene is known (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-181425 [Patent Document 2] Patent No. 5862486 Summary of the Invention [Problem to be solved by the invention]

[0006] Furthermore, fillers such as organic particles or inorganic particles are added to extrusion-molded sheets to reduce the relative proportion of resin and to form porosity and create a paper-like texture. However, systems containing fillers are more likely to cause molding defects than systems not containing fillers due to the non-uniformity caused by the fillers.

[0007] In filler-containing systems, improving the fluidity of the resin contributes to suppressing draw resonance, but it can worsen the non-uniformity of the filler, which can lead to molding defects. Such filler-containing systems have higher melt tensions than systems that do not contain fillers, and simply applying the techniques described in Patent Documents 1 and 2 can further increase the tension, making the edges more susceptible to breakage between air gaps during extrusion and making molding difficult.

[0008] The present invention increases the molding speed in filler-containing systems without causing molding defects. Another object of the present invention is to provide an extrusion-molded sheet that is less susceptible to draw resonance even when the sheet is thinned, a laminate using the extrusion-molded sheet, and a resin composition for use in the extrusion-molded sheet. [Means for solving the problem]

[0009] As a result of intensive research conducted by the present inventors to solve the above problems, they discovered that by adjusting the balance between strain hardening and fluidity, draw resonance can be suppressed without causing molding defects, and thus completed the present invention. That is, the present invention is as follows.

[0010] [1] 230℃, strain rate 1sec -1 The strain hardening measured under the conditions is 0.05 to 0.4, 230℃, swing angle 1%, angular frequency 1s -1 The complex viscosity measured under the conditions is tripled to 3η + is 2000 to 15000, An extruded sheet containing a filler. [2] The extrusion-molded sheet according to [1], which contains a polyolefin-based resin. [3] The extrusion-molded sheet according to [1] or [2], which is porous. [4] The extrusion-molded sheet according to any one of [1] to [3], which is a stretched layer stretched in at least one direction. [5] The extrusion-molded sheet according to [4], further comprising high-density polyethylene. [6] The extrusion-molded sheet according to any one of [2] to [4], wherein the polyolefin-based resin contains a polypropylene-based resin having a branched chain. [7] The extrusion-molded sheet according to any one of [1] to [6], wherein the content of the filler is 3 to 60 mass %. [8] The extrusion-molded sheet according to any one of [1] to [7], wherein the filler has an average particle size of 0.01 to 25 μm. [9] The extrusion-molded sheet according to any one of [1] to [8], wherein the filler is calcium carbonate.

[10] A substrate layer and an extrusion laminate layer provided on at least one surface of the substrate layer, The extrusion laminate layer comprises the extrusion-molded sheet according to any one of [1] to [9].

[11] The laminate according to

[10] , which is for printing.

[12] 230℃, strain rate 1sec -1 The strain hardening measured under the conditions is 0.05 to 0.4, 230℃, swing angle 1%, angular frequency 1s -1 The complex viscosity measured under the conditions is tripled to 3η + is 2000 to 15000, A resin composition for extrusion molding, containing a filler. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an extrusion-molded sheet in a filler-containing system that is less likely to cause draw resonance even when the molding speed is increased and the sheet is made thinner without causing molding defects, a laminate using the extrusion-molded sheet, and a resin composition for use in the extrusion-molded sheet. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the extrusion-molded sheet of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the laminate of the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing an example of the laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The extrusion-molded sheet and the resin composition for extrusion molding of the present invention will be described in detail below. The following is an example (typical example) of the present invention, and the present invention is not limited to this.

[0014] [Resin composition for extrusion molding] The extrusion-molded sheet of the present invention is obtained by extrusion molding the resin composition for extrusion molding of the present invention. The resin composition for extrusion molding of the present invention contains a filler, has a strain hardening degree of 0.05 to 0.4, and a complex viscosity triple value 3η + is between 2000 and 15000. Strain hardening and 3η + When the value of the thickness of the extrusion-molded sheet is within the above-mentioned specific range, it is possible to obtain an extrusion-molded sheet in which the occurrence of draw resonance is suppressed even when a filler is contained.

[0015] <Filler> The resin composition for extrusion molding of the present invention contains a filler, which allows the proportion of plastic to be relatively reduced. Furthermore, the filler forms fine pores within the sheet, making it porous, allowing the stiffness, whiteness, or opacity of the sheet to be adjusted, and giving the sheet a paper-like texture. Examples of fillers that can be used include inorganic fillers and organic fillers, which can be used alone or in combination.

[0016] Examples of inorganic fillers include inorganic fine powders such as calcium carbonate, calcined clay, talc, titanium oxide, barium sulfate, zinc oxide, magnesium oxide, diatomaceous earth, and silicon oxide; composite inorganic fine powders having aluminum oxide or hydroxide surrounding the nucleus of an inorganic fine powder; and hollow glass beads. Among these, calcium carbonate, calcined clay, and diatomaceous earth are preferred because they are inexpensive and can form many pores by stretching. Examples of calcium carbonate include heavy calcium carbonate and light calcium carbonate.

[0017] From the viewpoint of pore formation, the organic filler is preferably a resin having a melting point or glass transition point higher than that of the resin used in the sheet and being incompatible with the resin used in the sheet. Specific examples of the organic filler include polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, homopolymers or copolymers of (meth)acrylic acid esters, melamine resins, polyethylene sulfite, polyimide, polyethyl ether ketone, polyphenylene sulfide, homopolymers of cyclic olefins, copolymers (COC) of cyclic olefins and ethylene, etc. When a crystalline polyolefin resin is used as the resin for the sheet, it is preferable to use, as the organic filler, polyethylene terephthalate, polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, polystyrene, homopolymers of cyclic olefins, and copolymers (COC) of cyclic olefins and ethylene, etc.

[0018] The average particle size of the filler is preferably 0.01 μm or more, more preferably 0.1 μm or more, even more preferably 1 μm or more, and preferably 25 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, even more preferably 5 μm or less, and particularly preferably 3 μm or less. When the average particle size is 0.01 μm or more, the filler does not aggregate in the resin and is dispersed uniformly, which tends to result in good draw resonance. Also, when the particle size is 25 μm or less, the entanglement of the resin molecular chains is not inhibited, which not only results in good draw resonance but also tends to prevent poor appearance due to surface breakage during stretching.

[0019] Furthermore, from the viewpoint of suppressing the inhibition of the effect of the strain-hardening resin, the aspect ratio of the filler is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 to 2. Examples of the shape of such a filler include spherical and irregular shapes.

[0020] The content of the filler in the resin composition for extrusion molding (the total amount when an inorganic filler and an organic filler are used in combination) is preferably 3% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, because this facilitates imparting opacity to the film, etc. Also, in order to improve draw resonance by blending the resin and to maintain the filler in a dispersed state, the content is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 50% by mass or less.

[0021] <Strain hardening> The resin composition for extrusion molding of the present invention has a strain hardening coefficient of 0.05 to 0.4. Strain hardening is an index that represents strength during melting and elongation. High strain hardening improves viscosity near the take-up roll, thereby suppressing draw resonance during extrusion molding. High strain hardening also improves melt tension, thereby suppressing neck-in during extrusion molding. On the other hand, controlling strain hardening to a low level eliminates uneven stress distribution in the air gap (the space from the extrusion outlet of the die to the take-up roll) caused by excessive tension increase near the take-up roll, thereby suppressing deterioration of draw resonance and breakage during molding. From this perspective, the strain hardening is 0.05 or more, preferably 0.08 or more, and more preferably 0.15 or more. Furthermore, the strain hardening is 0.4 or less, preferably 0.37 or less, and more preferably 0.34 or less.

[0022] A specific method for measuring the strain hardening degree will be explained in the examples.

[0023] <Complex viscosity> The resin composition for extrusion molding of the present invention has a complex viscosity three times the value 3η + is between 2000 and 15000. Complex viscosity is an index that represents viscosity coefficient, and for general resins, the higher the complex viscosity, the lower the fluidity tends to be. + When 3η is set to the above lower limit value or more, aggregation of the filler and deterioration of dispersibility can be suppressed, and molding defects can be reduced. + By setting 3η to the above upper limit or less, the increase in resin pressure during extrusion and the resulting opening of the lip of the extrusion port can be suppressed, and draw resonance can be suppressed. + is 2000 or more, preferably 4000 or more, and more preferably 5000 or more. + is 15,000 or less, preferably 14,000 or less, and more preferably 13,000 or less.

[0024] The complex viscosity of the resin composition is 230°C, oscillation angle 1%, angular frequency 1s -1 The value is obtained by measuring using a viscoelasticity measuring device under the conditions.

[0025] <Polyolefin resin> The resin used in the resin composition for extrusion molding of the present invention is a thermoplastic resin, and is not particularly limited. However, from the viewpoint of mechanical strength, a polyolefin-based resin is preferred, and a polypropylene-based resin or a polyethylene-based resin is particularly preferred. In addition, in order to set the strain hardening degree and complex viscosity triple value of the resin composition within the above-mentioned specific ranges, the resin composition preferably contains a resin having strain hardening properties. Strain hardening properties refer to the property of increasing viscosity due to strain. Specific examples of resins having strain hardening properties include branched chain resins and ultra-high molecular weight resins.

[0026] Examples of branched polyolefin resins include long-chain branched polypropylene resins and low-density polyethylene resins (density 0.910 to 0.930 g / cm 3 ), low-density polyethylene ionomer resins, etc. The long-chain branching can be confirmed by calculating the branching index g', which can be calculated using the following formula. If the branching index g' is a value smaller than 1, it can be determined that the polymer has a long-chain branched structure. The long-chain branched structure is distinguished from the short-chain branched structure formed by copolymerization with an α-olefin such as 1-butene. Branching index g'=Vbr / Vlin Vbr represents the intrinsic viscosity of the resin having a structure with long chain branches, and Vlin represents the intrinsic viscosity of a linear resin having the same molecular weight as the resin having a structure with long chain branches. Examples of ultra-high molecular weight polyolefin resins include ultra-high molecular weight polyethylene resins. In particular, polypropylene resins with long chain branches are preferred from the viewpoint of heat resistance, and polypropylenes produced by macromer copolymerization using a combination of metallocene catalysts are particularly preferred. Commercially available polypropylenes can also be used, and Waymax MFX3, Waymax MFX6, Waymax MFX8, and the like manufactured by Japan Polypropylene Corporation are preferably used. Two or more strain-hardening resins may be used in combination.

[0027] The content of the strain-hardening resin in the resin composition for extrusion molding is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and even more preferably 5 to 20% by mass. Within this range, the strain hardening of the resin composition is in a sufficient range, resulting in good moldability, and the melt tension does not become too high, which tends to reduce the risk of deterioration of draw resonance and breakage during molding.

[0028] The resin composition for extrusion molding may further contain other resins in addition to the strain-hardening resin. Examples of other resins include linear polyolefin resins such as high-density polyethylene resins, medium-density polyethylene resins, linear low-density polyethylene resins, linear polypropylene resins, and polymethyl-1-pentene, polyamide resins such as nylon-6, nylon-6,6, nylon-6,10, and nylon-6,12, thermoplastic polyester resins such as polyethylene naphthalate and aliphatic polyester, and thermoplastic resins such as polycarbonate, atactic polystyrene, syndiotactic polystyrene, and polyphenylene sulfide.

[0029] When the extrusion-molded sheet is a stretched layer, the resin composition for extrusion molding preferably further contains a high-density polyethylene resin. 3 The high-density polyethylene resin has a density of 100 to 500 parts by mass. When the extrusion-molded sheet further contains a high-density polyethylene resin, the extrusion-molded sheet has improved ductility and is able to suppress breakage and thickness variations during stretching. The content of the high-density polyethylene resin in the extrusion-molded sheet is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more, per 100 parts by mass of the strain-hardening resin. Furthermore, in order to keep the strain hardening degree of the extrusion-molded sheet within a predetermined range, the content of the high-density polyethylene resin in the extrusion-molded sheet is preferably 500 parts by mass or less, more preferably 300 parts by mass or less, and even more preferably 100 parts by mass or less.

[0030] The other resin preferably includes a linear polyolefin resin, more preferably a linear polypropylene resin. Two or more of these may be mixed together. To ensure that the strain hardening of the resin composition for extrusion molding falls within a predetermined range, the content of the other resin is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 200 parts by mass or more, per 100 parts by mass of the strain-hardening resin. Furthermore, the content of the other resin is preferably 2,000 parts by mass or less, more preferably 1,000 parts by mass or less, and even more preferably 500 parts by mass or less, per 100 parts by mass of the strain-hardening resin.

[0031] <Other ingredients> The resin composition for extrusion molding may contain any known additives as needed, such as dispersants, antioxidants, light stabilizers, ultraviolet absorbers, crystal nucleating agents, antiblocking agents, plasticizers, slip agents such as fatty acid amides, dyes, pigments, release agents, and flame retardants.

[0032] A dispersant is an optional component added to enhance the uniformity of dispersion of inorganic filler powder. The dispersant may be present as a surface treatment agent for the inorganic filler. Examples of dispersants include silane coupling agents, higher fatty acids such as oleic acid and stearic acid, metal soaps, polyacrylic acid, polymethacrylic acid, and salts thereof. Among these, higher fatty acids or metal soaps are preferred, particularly in terms of preventing poor appearance due to surface breakage caused by inorganic filler aggregation or foreign matter when the extrusion laminate layer is a stretched layer. At least one compound selected from the group consisting of acids having a hydrocarbon group with 8 to 20 carbon atoms, esters of such acids, and salts thereof is more preferred. The content of the dispersant in the resin composition for extrusion molding is preferably 0.01% by mass or more, more preferably 1% by mass or more, because sufficient dispersibility is easily achieved. The content of the dispersant is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, because this easily prevents aggregation of the inorganic filler powder.

[0033] The resin composition for extrusion molding of the present invention having the above-described configuration suppresses the occurrence of draw resonance during extrusion molding. In extrusion molding, the greater the ratio of the take-up speed to the extrusion speed (take-up speed / extrusion speed = draft ratio), the more likely draw resonance occurs. Attempting to reduce the molding speed in order to suppress this draw resonance results in a decrease in productivity.

[0034] [Extrusion molding sheet] The extrusion-molded sheet of the present invention is obtained by extrusion molding the resin composition for extrusion molding of the present invention. The extrusion-molded sheet of the present invention contains a filler, has a strain hardening degree of 0.05 to 0.4, and a complex viscosity triple value 3η + is between 2000 and 15000. As described above, the strain hardening and complex viscosity are measured at 230°C, at which temperature the resin is in a molten state. Therefore, the strain hardening and complex viscosity of the resin composition for extrusion molding and the extrusion-molded sheet are the same.

[0035] The thickness of the extrusion-molded sheet is preferably 20 μm or more, more preferably 30 μm or more, from the viewpoints of mechanical strength and transportability during printing, and is preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 500 μm or less, still more preferably 200 μm or less, and particularly preferably 130 μm or less, from the viewpoints of reducing production costs and waste plastics. When the extrusion-molded sheet is a stretched sheet, the thickness of the extrusion-molded sheet is preferably within the range obtained by dividing the above thickness by the stretch ratio.

[0036] The extrusion-molded sheet may have a single-layer structure or a multi-layer structure of two or more layers. In the case of a multi-layer structure, at least one layer is obtained by extrusion molding the resin composition for extrusion molding of the present invention. The extrusion-molded sheet 10 shown in Figure 1 has a single-layer structure.

[0037] The extrusion-molded sheet is preferably a stretched layer that has been stretched in at least one direction. Stretching facilitates obtaining a thickness and stiffness that are excellent for various printability as printing paper, and also alleviates variations in the total thickness of the printing paper (thickness deviation), making it easier to obtain a uniform thickness and a smooth surface.

[0038] [Laminate] The laminate of the present invention comprises a substrate layer and an extrusion laminate layer provided on at least one surface of the substrate layer, and the extrusion laminate layer includes the extrusion-molded sheet of the present invention. Laminate 20A shown in Fig. 2 comprises substrate layer 2 and extrusion laminate layer 1A provided on one surface of substrate layer 2. The multilayer structure allows for the addition of various functions, such as printability, coatability, abrasion resistance, labeling suitability, and secondary processing suitability.

[0039] <Base material layer> The substrate layer is provided as a support for the laminate. As the resin constituting the substrate layer, a polyolefin resin is preferred from the viewpoint of mechanical strength, and a polypropylene resin or a polyethylene resin is preferred from the viewpoint of film formability.

[0040] The substrate layer may contain a filler. Examples of the filler that can be used include the inorganic fillers and organic fillers used in the resin composition for extrusion molding and the extrusion-molded sheet described above.

[0041] The substrate layer may further contain a heat stabilizer (antioxidant), a light stabilizer, a dispersant, a lubricant, a nucleating agent, or the like, as needed.

[0042] The substrate layer may have a single layer structure, or a multi-layer structure of two or more layers.

[0043] From the viewpoint of mechanical strength and transportability during printing, the thickness of the substrate layer is preferably 10 μm or more, more preferably 15 μm or more, and is preferably 800 μm or less, more preferably 400 μm or less, and particularly preferably 150 μm or less. The base layer is preferably a stretched layer stretched in at least one direction. Stretching facilitates obtaining a thickness and stiffness that are excellent for various printability as a printing paper, and also reduces variations in the total thickness of the printing paper, making it easier to obtain a uniform thickness and a flat surface.

[0044] <Extrusion laminate layer> The extrusion laminate layer in the laminate of the present invention comprises the extrusion-molded sheet of the present invention. In extrusion molding, a smaller air gap (the distance between the extruded resin and the substrate layer) is advantageous from the perspective of suppressing draw resonance. On the other hand, when laminating an extrusion laminate layer to a substrate layer, the width of the extrusion laminate layer must be adjusted to match the width of the substrate layer. Changing the air gap is one possible method for achieving this. However, changing the air gap can result in a change in the width of the extrusion laminate layer due to a neck-in phenomenon, in which the film thickness at both edges of the extruded resin increases before reaching the substrate layer. Therefore, changing the air gap for the purpose of suppressing draw resonance is difficult. Therefore, by using the extrusion laminate layer as an extrusion-molded sheet of the present invention, which has the above-mentioned specific strain hardening and complex viscosity ranges, we have approached draw resonance suppression from the perspective of the material of the extrusion laminate layer itself.

[0045] The extrusion laminate layer may be a single layer structure, or a multi-layer structure of two or more layers, in which at least one layer is the extrusion-molded sheet of the present invention.

[0046] The extrusion laminate layer may be provided on one or both sides of the base layer. The laminate 20A shown in Fig. 2 has an extrusion laminate layer 1A provided on one side of the base layer 2. The laminate 20B shown in Fig. 3 has extrusion laminate layers 1A and 1B provided on both sides of the base layer 2.

[0047] The thickness of the extrusion laminate layer is preferably 5 μm or more, more preferably 8 μm or more, and from the viewpoint of making it possible to add various functions while keeping the overall laminate thin, it is preferably 400 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less. When the extrusion laminate layer is a stretched layer, the thickness of the extrusion laminate layer is preferably within the range obtained by dividing the above thickness by the stretch ratio.

[0048] The extrusion laminate layer is preferably a stretched layer stretched in at least one direction. Stretching facilitates obtaining thickness dimensions and stiffness that are excellent for various printability as printing paper, and also alleviates variations in the total thickness dimension of the printing paper, making it easier to obtain a uniform thickness and a flat surface. On the other hand, from the viewpoint of preventing surface breakage, the extrusion laminate layer is preferably a non-stretched layer.

[0049] From the viewpoint of reducing manufacturing costs and reducing plastic waste, the thickness of the laminate is preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 500 μm or less, and particularly preferably 200 μm or less. From the viewpoint of mechanical strength, the thickness is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The thickness of the laminate is measured, for example, according to JIS K7130:1999 "Plastics - Films and Sheets - Thickness Measurement Method."

[0050] The laminate of the present invention is useful for printing, and can be printed on both sides of the laminate. The printing method is not particularly limited, and commonly used methods such as gravure printing, screen printing, and flexographic printing can be used.

[0051] [Method of manufacturing extrusion-molded sheets and laminates] The extrusion-molded sheets and laminates of the present invention can be produced by known methods. Examples of methods for producing extrusion-molded sheets include cast molding, calendar molding, roll molding, inflation molding, and the like, in which a resin composition containing a resin, a filler, etc. is melted and extruded into a sheet using a T-die, I-die, or the like connected to a screw-type extruder. The laminate may be produced by forming the base layer and the extrusion laminate layer separately and then laminating them, or by using a conventional method such as a feed block, a multi-layer die method using a multi-manifold, or an extrusion lamination method using multiple dies, in which the base layer and the extrusion laminate layer are formed and laminated in parallel.

[0052] The extrusion-molded sheet and each layer constituting the laminate may be an unstretched film or a uniaxially or biaxially stretched film, but from the viewpoint of improving pore formability and mechanical strength, a stretched film is preferred.

[0053] For example, by stretching the extrusion-molded sheet or the laminate in a uniaxial or biaxial direction at a temperature lower than the melting point of the thermoplastic resin used in each layer, a stretched film in which all layers are stretched in a uniaxial or biaxial direction can be obtained.

[0054] Furthermore, in the laminate, a uniaxially / biaxially stretched film can be obtained by laminating an extrusion laminate layer on a uniaxially stretched substrate layer and then uniaxially stretching the extrusion laminate layer in a direction different from that of the substrate layer. The substrate layer and the extrusion laminate layer may be stretched separately and then laminated, but it is preferable to stretch the layers together after laminating them, as this is simpler and reduces production costs.

[0055] Examples of the stretching method include inter-roll stretching utilizing the difference in peripheral speed between a group of rolls, clip stretching using a tenter oven, etc. Inter-roll stretching is preferred because it allows the desired stretch ratio to be adjusted to easily obtain the desired rigidity, opacity, smoothness, gloss, etc.

[0056] The stretching temperature is usually 5 to 60° C. lower than the melting point of the resin. When two or more resins are used, the stretching temperature is preferably usually 5° C. or more lower than the melting point of the resin that is blended in the largest amount. [Example]

[0057] The present invention will be explained in more detail below with reference to Production Examples, Examples, Comparative Examples, and Test Examples. The materials, amounts used, proportions, treatment details, treatment procedures, etc. shown in the Production Examples and Examples can be appropriately changed without departing from the scope of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0058] The materials used are listed below. <Polyolefin resin> Propylene homopolymer A: manufactured by Japan Polypropylene Corporation, trade name: Novatec PP FY6, MFR (230°C, 2.16 kg load): 2.5 g / 10 min Propylene homopolymer B: manufactured by Japan Polypropylene Corporation, trade name: Novatec PP MA3, MFR (230°C, 2.16 kg load): 11 g / 10 min Propylene homopolymer C: manufactured by Japan Polypropylene Corporation, trade name: Waymax MFX3, MFR (230°C, 2.16 kg load): 9.0 g / 10 min, branching index: 0.85 Propylene homopolymer D: manufactured by Japan Polypropylene Corporation, trade name: Waymax MFX6, MFR (230°C, 2.16 kg load): 2.5 g / 10 min, branching index: 0.88 High-density polyethylene: Made by Japan Polyethylene Co., Ltd., product name: Novatec HD HJ381, MFR (190°C, 2.16 kg load): 11 g / 10 min

[0059] <Filler> Calcium carbonate A: manufactured by Bihoku Funka Kogyo Co., Ltd., product name: Softon 1800, average particle size: 1.25 μm, aspect ratio: 1.78 Calcium carbonate B: manufactured by Bihoku Funka Kogyo Co., Ltd., product name: Softon 3200, average particle size: 0.7 μm Calcium carbonate C: Maruo Calcium Co., Ltd., product name: YM30, average particle size: 0.3 μm, fatty acid surface treatment Calcium carbonate D: manufactured by Bihoku Funka Kogyo Co., Ltd., product name: BF200, average particle size: 5 μm

[0060] [Examples 1 to 7, Comparative Examples 1 to 3] The raw materials shown in Table 1 were kneaded in a twin-screw kneader, extruded into strands, and cut to obtain pellets (Resin Compositions 1-1 to 1-6). The resulting pellets were melt-kneaded in a 40 mm diameter extruder set at 250°C, extruded at a speed of 4 m / min through a T-die (die width 230 mm, die lip opening 0.8 mm) attached to the extruder, and taken up at a speed of 30 m / min (air gap 60 mm) on a cooling roll (surface temperature 40°C) to obtain a single-layer cast extrusion sheet with a thickness of 130 μm.

[0061] <3η + > Using a viscoelasticity measuring device (Anton Paar MCR301), the temperature was 230°C, the oscillation angle was 1%, and the angular frequency was 1 s -1 The complex viscosity (Pa·s) of the resin compositions obtained in the examples and comparative examples was measured under the conditions of + was calculated.

[0062] <Strain hardening> Rheometric Scientific ARES-2000 at 230°C and a strain rate of 1 sec -1 The elongational viscosity (ηe + ) was measured. When the elongational viscosity was plotted against time, the slope of the plot was constant within the range of strain amounts 1 to 4. + (ε1) was extracted three or more times. The nonlinear parameter (λn) for each plot was calculated using the following relationship: λn=ηe + (ε1) / 3η + ηe + (ε1): strain rate 1 (sec -1 ) Extensional viscosity when 3η + : Three times the complex viscosity (Pa s) calculated above The strain hardening (SH) was calculated using the nonlinear parameter (λn) according to the following formula: SH=dLn(λn) / dε

[0063] <Limit draft ratio> The extrusion speed (m / min) was reduced, and the draft ratio (take-up speed / extrusion speed) was calculated from the extrusion speed at which draw resonance occurred, and this value was taken as the limiting draft ratio. Draw resonance was determined by visually observing the vibration of the sheet edge and measuring the thickness unevenness in the flow direction of the sampled sheet. Thickness deviation of 20 μm or more was considered to be draw resonance. Limit draft ratio (A to D pass) A: 14.5 or higher B: 13 or more and less than 14.5 C: 11.5 or more and less than 13 D: 10 or more and less than 11.5 E: 8 or more but less than 10 F: Less than 8

[0064] <Neck-in> In the above extrusion molding, the sheet width was measured at an extrusion speed of 2.5 m / min. The reduction in width from the die width of 230 mm was taken as the neck-in amount. Neck-in amount (A or B is acceptable) A: Less than 24mm B: 24mm or more and less than 30mm C: 30mm or more and less than 35mm D:35mm or more

[0065] <Uneven thickness> The thickness of the obtained extrusion molded sheet was measured in accordance with JIS K7130:1999 "Plastics - Films and sheets - Thickness measurement method", and the difference between the maximum and minimum values ​​was taken as the thickness deviation.

[0066] Table 1 shows the evaluation results of resin compositions 1-1 to 1-10. Table 2 shows the evaluation results of the extrusion-molded sheets of Examples 1 to 7 and Comparative Examples 1 to 3.

[0067] [Table 1]

[0068] [Table 2]

[0069] From the above results, the strain hardening and 3η + The extrusion-molded sheets of Examples 1 to 7, which used resin compositions 1-1 to 1-7, each of which had values ​​within the specified range, exhibited good results in both the limit draft ratio and neck-in, and were excellent in moldability. + The extrusion-molded sheets of Comparative Examples 1 to 3, which used resin compositions 1-8 to 1-10, respectively, in which any one of the above was outside the specified range, resulted in poor improvement in the critical draft ratio in particular.

[0070] [Example 8] The raw materials shown in Table 1 were kneaded in a twin-screw kneader, extruded into strands, and cut to obtain pellets (Resin Composition 2-1). The obtained pellets were melt-kneaded in an extruder set at 250°C and extruded into a sheet to obtain an unstretched sheet. Next, this unstretched sheet was reheated to 150°C and then stretched 4.8 times in the sheet flow direction using the speed difference between the rolls to obtain a longitudinally stretched resin film. Next, resin composition 1-1 shown in Table 1 was melt-kneaded in an extruder with a diameter of 40 mm set at 250°C, extruded onto both sides of the base layer at a speed of 2.5 m / min and laminated thereon. The resulting laminate was then taken up (air gap 60 mm) at a speed of 30 m / min with a cooling roll (surface temperature 40°C) to obtain a laminated sheet having an extruded laminate layer with a thickness of 100 μm. The resulting laminate sheet was cooled to 60°C, reheated to 150°C, stretched 9 times in the sheet width direction using a tenter, and then annealed at 165°C. It was then cooled again to 60°C to obtain a three-layer structure (uniaxially stretched / biaxially stretched / uniaxially stretched) laminate with a total thickness of 60 μm (extruded laminate layer / base layer / extruded laminate layer = 11 μm / 38 μm / 11 μm).

[0071] [Example 9] A laminate was obtained in the same manner as in Example 8, except that the resin composition for the base layer was changed to 2-2.

[0072] [Example 10] The raw materials shown in Table 1 were kneaded in a twin-screw kneader, extruded into strands, and cut to obtain pellets (Resin Composition 2-1). The obtained pellets were melt-kneaded in an extruder set at 250°C and extruded into a sheet to obtain an unstretched sheet. Next, this unstretched sheet was reheated to 150°C and then stretched 4.8 times in the sheet flow direction using the speed difference between the rolls to obtain a longitudinally stretched resin film. The resulting laminated sheet was then cooled to 60°C, reheated to 150°C, stretched 9 times in the sheet width direction using a tenter, and then annealed at 165°C. Thereafter, the sheet was cooled again to 60°C to obtain a biaxially stretched resin film with a thickness of 38 μm. Resin composition 1-1 shown in Table 1 was melt-kneaded in a 40 mm diameter extruder set to 250°C, extruded onto both sides of a biaxially oriented resin film at a speed of 2.5 m / min, and then taken up (air gap 60 mm) at a speed of 30 m / min with a cooling roll (surface temperature 40°C) to obtain a three-layer structure (unstretched / biaxially stretched / unstretched) laminate with a total thickness of 238 μm (extruded laminate layer / base layer / extruded laminate layer = 100 μm / 38 μm / 100 μm).

[0073] [Example 11] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-2.

[0074] [Example 12] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-3.

[0075] [Example 13] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-4.

[0076] [Example 14] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-5.

[0077] [Example 15] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-6.

[0078] [Example 16] A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-7.

[0079] Comparative Example 4 A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-8.

[0080] Comparative Example 5 A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-9.

[0081] Comparative Example 6 A laminate was obtained in the same manner as in Example 8, except that the resin composition of the extrusion laminate layer was changed to 1-10.

[0082] <Extrusion laminate layer formability> The edge vibration of a laminated sheet (before being stretched to form a laminate) with a thickness of 100 μm was visually observed, and the thickness unevenness in the flow direction of the sampled sheet was measured. Sheets with a thickness deviation of 20 μm or more were determined to be draw resonance generating sheets. A: No draw resonance occurred during molding, and no thickness unevenness occurred. C: Draw resonance occurred during molding, causing thickness unevenness. (A passed)

[0083] <Surface damage> Laminated body 1m 2 The number of foreign objects visible to the naked eye and the number of surface tears caused by foreign objects were counted. Number of surface tears (○ or △ is pass) ○: Less than 2 △: 2 or more but less than 6 ×:6 or more

[0084] The evaluation results of Examples 8 to 16 and Comparative Examples 4 to 6 are shown in Table 3.

[0085] [Table 3]

[0086] From the above results, the strain hardening and 3η + The laminates of Examples 8 to 16, in which resin compositions 1-1 to 1-7, each of which had values ​​within the specified ranges, were used for the laminate layer, did not experience draw resonance during molding and were excellent in extrusion laminate layer moldability. The laminate of Example 10 had a large thickness deviation due to the inclusion of a non-stretched layer, but the extrusion laminate layer formability was good. The laminates of Examples 12 to 14 contain a filler in the laminate layer. In the laminate of Example 12, the filler had a small particle size, which made it prone to aggregation and caused surface breakage. In the laminate of Example 14, the filler had a large particle size, which inhibited entanglement of the resin, causing thickness deviation and surface breakage. In the laminate of Example 13, the use of a surface-treated filler improved dispersibility, and no surface breakage occurred. In the laminate of Example 15, resin composition 1-6 containing high-density polyethylene was used in the laminate layer, and therefore, the extensibility was improved, and the occurrence of surface breakage and uneven thickness could be suppressed.

[0087] On the other hand, the strain hardening rate and 3η +In the laminates of Comparative Examples 4 to 6, in which resin compositions 1-8 to 1-10, each of which had any of the above properties outside the specified range, were used for the extrusion laminate layer, draw resonance occurred during molding, and the moldability of the extrusion laminate layer was not good. [Explanation of symbols]

[0088] 10...extrusion-molded sheet, 20A, 20B...laminate, 1A, 1B...extrusion laminate layer, 2...base material layer

Claims

1. 230°C, strain rate 1 sec －１ The strain hardening degree measured under the conditions is 0.05 to 0.4, 230°C, swing angle 1%, angular frequency 1s －１ The complex viscosity measured under the conditions is tripled to 3η ＋ is 2000 to 15000, The composition contains a filler, a branched polyolefin resin, and a linear polyolefin resin, The extrusion-molded sheet, wherein the content of the linear polyolefin resin is 50 parts by mass or more and 2000 parts by mass or less per 100 parts by mass of the branched polyolefin resin.

2. 10. The extruded sheet of claim 1 which is porous.

3. The extrusion-molded sheet according to claim 1 or 2, which is a stretched layer stretched in at least one direction.

4. 4. The extruded sheet of claim 3 further comprising high density polyethylene.

5. The extrusion-molded sheet according to claim 1 or 2, wherein the branched polyolefin resin contains a branched polypropylene resin.

6. The branched polyolefin resin is a branched polyethylene resin or a branched polypropylene resin, when the branched polyolefin resin is the branched polyethylene resin, the linear polyolefin resin is at least one selected from a high-density polyethylene resin, a medium-density polyethylene resin, and a linear low-density polyethylene resin, 3. The extrusion-molded sheet according to claim 1, wherein when the branched polyolefin resin is the branched polypropylene resin, the linear polyolefin resin is a linear polypropylene resin.

7. An extrusion-molded sheet as described in claim 1 or 2, wherein the branched polyolefin resin is a branched polypropylene resin, and the linear polyolefin resin is a linear polypropylene resin.

8. The extrusion-molded sheet according to claim 1 or 2, wherein the filler content is 3 to 60 mass%.

9. 3. The extrusion-molded sheet according to claim 1, wherein the filler has an average particle size of 0.01 to 25 μm.

10. 3. The extrusion molded sheet of claim 1, wherein the filler is calcium carbonate.

11. a base layer and an extrusion laminate layer provided on at least one surface of the base layer; A laminate, wherein the extrusion laminate layer comprises the extrusion-molded sheet according to claim 1 or 2.

12. The laminate of claim 11 for use in printing.

13. 230°C, strain rate 1 sec －１ The strain hardening degree measured under the conditions is 0.05 to 0.4, 230°C, swing angle 1%, angular frequency 1s －１ The complex viscosity measured under the conditions is tripled to 3η ＋ is 2000 to 15000, The composition contains a filler, a branched polyolefin resin, and a linear polyolefin resin, The resin composition for extrusion molding, wherein the content of the linear polyolefin resin is 50 parts by mass or more and 2000 parts by mass or less per 100 parts by mass of the branched polyolefin resin.

14. The branched polyolefin resin is a branched polyethylene resin or a branched polypropylene resin, when the branched polyolefin resin is the branched polyethylene resin, the linear polyolefin resin is at least one selected from a high-density polyethylene resin, a medium-density polyethylene resin, and a linear low-density polyethylene resin, 14. The resin composition for extrusion molding according to claim 13, wherein when the branched polyolefin resin is the branched polypropylene resin, the linear polyolefin resin is a linear polypropylene resin.

15. A resin composition for extrusion molding as described in Claim 13, wherein the polyolefin resin having a branched chain is a polypropylene resin having a branched chain, and the linear polyolefin resin is a linear polypropylene resin.

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