Glass protective material and method for producing long fiber nonwoven fabric

Abstract

The purpose of the present invention is to provide a glass protective material which has high grip properties with respect to glass, and has impact absorption properties even though the thickness thereof is thin. The present invention relates to a glass protective material which contains a long fiber nonwoven fabric, and the present invention is characterized in that: the long fiber nonwoven fabric is composed of fibers that contain a thermoplastic resin; the melt flow rate (MFR) of the thermoplastic resin under the conditions of 190°C and a load of 2.16 kg is 0.3-80 g / 10 min; the thickness is 0.2 mm to 0.8 mm inclusive; and the frictional resistance value to glass is 0.8 or more.

Description

Glass protection material and method for manufacturing long-fiber nonwoven fabric

[0001] The present invention relates to a glass protective material containing a long-fiber nonwoven fabric and a method for producing the long-fiber nonwoven fabric, and is useful as a glass protective material containing a long-fiber nonwoven fabric that can efficiently protect glass by suppressing glass slippage and absorbing external impacts in order to protect the glass surface during transportation or storage, for example, in plate glass used in liquid crystal panels, etc.

[0002] BACKGROUND ART In recent years, foam sheets made of polyolefin resins have been widely used as cushioning materials between glass plates to prevent damage to display panels such as liquid crystal displays and organic electroluminescent displays during storage and transportation.

[0003] For example, Patent Document 1 describes a glass protection sheet made of polyethylene, and discloses a polyethylene foam sheet that exhibits good impact absorption properties by foaming polyethylene.

[0004] Furthermore, Patent Document 2 discloses a slip sheet made mainly of pulp that is sandwiched between glass plates to prevent scratches on the glass surface.

[0005] JP 2012-020766 A JP 2016-14205 A

[0006] The foamed sheet made of polyolefin as shown in Patent Document 1 has air bubbles that act as a buffer, so it is difficult to reduce the thickness of the buffer material itself, which reduces the loading efficiency of plate glass per volume and causes the problem of rising transportation costs.

[0007] Furthermore, the pulp paper disclosed in Patent Document 2 has a thin thickness, which increases loading efficiency, but its impact absorption is poor, increasing the risk of glass breakage during transportation.Furthermore, the nonwoven fabric has a poor grip on glass, which causes the glass to slip during transportation or storage, resulting in the problem of fine foreign matter adhering to the glass or the surface of the buffer material being rubbed and damaged.

[0008] The present invention aims to provide a glass protective material that is thin yet has impact absorption properties, thereby improving loading efficiency and preventing scratches caused by sliding of glass. Preferably, the glass protective material is made of a biodegradable long-fiber nonwoven fabric. Another object of the present invention is to provide a method for producing the long-fiber nonwoven fabric contained in the glass protective material.

[0009] As a result of intensive research into achieving the above object, the present inventors have found that a long-fiber nonwoven fabric obtained by using a thermoplastic resin having specific melting properties has impact absorption properties despite its thin thickness and is capable of increasing frictional resistance against glass, and have thus completed the following invention.

[0010] (1) A glass protection material comprising a long-fiber nonwoven fabric, the long-fiber nonwoven fabric being composed of fibers containing a thermoplastic resin, the thermoplastic resin having a melt flow rate (MFR) of 0.3 to 80 g / 10 min under conditions of 190°C and a load of 2.16 kg, a thickness of 0.2 mm to 0.8 mm, and a friction resistance against glass of 0.8 or more.

[0011] (2) The glass protection material or nonwoven fabric of (1) above preferably has an apparent density of 0.4 g / cc or less.

[0012] (3) In the configuration of (1) or (2), the thermoplastic resin is preferably at least one selected from polyamide-based resins, polystyrene-based resins, polyolefin-based resins, polyacetal-based resins, polycarbonate-based resins, polyvinyl chloride-based resins, AS resins, ABS resins, acrylic-based resins, polyester-based resins, polyvinyl alcohol-based resins, vinylidene chloride-based resins, and polyether-based resins.

[0013] (4) In any of the configurations (1) to (3), the thermoplastic resin is preferably a polyester resin.

[0014] (5) In any of the above (1) to (4), the thermoplastic resin is preferably an aromatic-containing polyester.

[0015] (6) In any of the configurations (1) to (5), it is preferable that the thermoplastic resin has a butylene skeleton.

[0016] (7) In any of the configurations (1) to (6), the thermoplastic resin preferably contains an adipic acid component, a terephthalic acid component, and a butanediol component in a total amount of 70 mol % or more, based on 100 mol % of all components.

[0017] (8) In any of the configurations (1) to (7) above, it is desirable that the melting point of the thermoplastic resin be within the range of 70°C or higher and 200°C or lower.

[0018] (9) In any of the configurations (1) to (8) above, it is desirable that the thermoplastic resin contains a biodegradable resin.

[0019] (10) In any one of the above (1) to (9), the biodegradable resin is preferably polybutylene adipate terephthalate.

[0020] (11) In any of the configurations (1) to (10), it is desirable that no mechanical entanglement treatment is performed.

[0021] (12) A method for producing a long-fiber nonwoven fabric contained in the glass protective material according to any one of (1) to (11), comprising: Step A of discharging a molten thermoplastic resin from a spinneret, cooling and solidifying the resin, and then pulling and stretching the resin with an ejector to form long fibers; Step B of collecting the long fibers obtained in Step A to form a long-fiber web; and Step C of pre-thermocompression bonding the long-fiber web.

[0022] According to the present invention, it is possible to provide a glass protective material that has impact absorption properties despite its thinness, thereby improving loading efficiency and suppressing scratches caused by sliding of glass. Preferably, such a glass protective material can be provided using a biodegradable long-fiber nonwoven fabric. The present invention also provides a method for producing the long-fiber nonwoven fabric contained in such a glass protective material.

[0023] In other words, in the present invention, since the MFR is within a predetermined range, crystallization of the resin constituting the resulting long-fiber nonwoven fabric is suppressed, thereby increasing flexibility and improving impact absorption and frictional resistance against glass. Furthermore, since the thickness is 0.2 mm or more and 0.8 mm or less, it is possible to increase the glass load per volume while maintaining impact resistance that prevents glass from being scratched during transportation. Furthermore, since the frictional resistance against glass is 0.8 or more, it is possible to suppress glass slippage during transportation or storage, preventing friction between the glass and foreign matter on the glass or the surface of the buffer material, thereby reducing the occurrence of scratches. Furthermore, when a long-fiber nonwoven fabric is produced using a biodegradable thermoplastic resin, the biodegradable long-fiber nonwoven fabric can provide such a glass protection material.

[0024] Hereinafter, embodiments of the present invention will be described in detail.

[0025] Examples of thermoplastic resins include polyamide resins, polystyrene resins, polyolefin resins, polyacetal resins, polycarbonate resins, polyvinyl chloride resins, acrylonitrile styrene resins (AS resins), acrylonitrile butadiene styrene resins (ABS resins), acrylic resins, polyester resins, polyvinyl alcohol resins, vinylidene chloride resins, polyether resins, etc. The thermoplastic resins can be random or block copolymers.

[0026] Examples of polyether-based resins include polylactic acid / polyether copolymers, examples of polyester-based resins include polylactic acid / polycaprolactone copolymers, and examples of polyolefin-based resins include ethylene / 1-hexene copolymers, ethylene / 1-octene copolymers, and ethylene / 1-butene copolymers.

[0027] The polyolefin resins include copolymers of olefin monomers such as ethylene, propylene, and 1-butene, and copolymers of olefin monomers with monomers copolymerizable with them, such as ethylene / α-olefin copolymers.

[0028] The polyester resin is not particularly limited as long as it is a condensation polymer of a polycarboxylic acid and a polyhydric alcohol and is obtained by dehydration condensation of a hydroxyl group of a polyhydric alcohol and a carboxylic group of a polycarboxylic acid.

[0029] Examples of polycarboxylic acids include aromatic dicarboxylic acids such as isophthalic acid, terephthalic acid, diphenyl ether-4,4'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, and naphthalene-2,6-dicarboxylic acid; aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, and undecadicarboxylic acid; and alicyclic dicarboxylic acids such as hexahydroterephthalic acid. Of the aliphatic dicarboxylic acids, adipic acid is preferred.

[0030] Examples of polyhydric alcohols include aliphatic glycols such as ethylene glycol, butanediol, propylene glycol, and neopentyl glycol; alicyclic glycols such as cyclohexanedimethanol; and aromatic dihydroxy compounds such as bisphenol A. The polyester resin is preferably a polymer containing one or more of the above-mentioned carboxylic acid components, and may also be a polymer containing one or more of the above-mentioned diol components. When the thermoplastic resin-containing fiber of the present invention is composed of a polyester resin, a single polyester resin may be used, or a blend of a homopolymer and a copolymer may be used. Examples of such polyester resins include polyethylene terephthalate resins, polybutylene succinate resins, polybutylene succinate adipate resins, polybutylene adipate terephthalate resins, polybutylene terephthalate resins, and polylactic acid resins. Polybutylene succinate adipate resins and polybutylene adipate terephthalate resins are preferred. Copolymer polyesters containing structural units derived from an aromatic carboxylic acid component and an aliphatic carboxylic acid component provide even better stretchability, and among these, copolymers containing a terephthalate skeleton as a structural unit are preferred.

[0031] The thermoplastic resin preferably has a crystalline melting enthalpy of 9 J / g or more. A crystalline melting enthalpy of 9 J / g or more can improve the strength of the nonwoven fabric. The crystalline melting enthalpy is more preferably 14 J / g or more, even more preferably 18 J / g or more, even more preferably 19 J / g or more, still more preferably 20 J / g or more, and particularly preferably 21 J / g or more.

[0032] The crystalline melting enthalpy (J / g) of the thermoplastic resin can be determined from the integral of the endothermic peak (melting peak) of the endothermic curve measured using a differential scanning calorimeter with a sample mass of 2.0 mg±0.1 mg at a heating rate of 20°C / min under a nitrogen atmosphere. The integral can be determined by setting the point where the curve relating to the endothermic peak (melting peak) starts to deviate from the baseline on the low temperature side as the starting point and the point where it starts to contact the baseline on the high temperature side as the end point, drawing a straight line connecting the start point and the end point, and integrating the area enclosed by the straight line and the curve.

[0033] The weight average molecular weight (g / mol) of the thermoplastic resin is preferably 35,000 or more. This can improve the strength of the nonwoven fabric. The weight average molecular weight is more preferably 37,000 or more, and even more preferably 40,000 or more. Also, 150,000 or less is preferable. When it is 150,000 or less, flexibility can be improved. Furthermore, when the weight average molecular weight is 120,000 or less, the polymer melt viscosity can be reduced, resulting in good yarn breakage resistance during spinning. The weight average molecular weight is more preferably 120,000 or less. The weight average molecular weight can be determined by gel permeation chromatography (GPC) or the like.

[0034] The melt flow rate (MFR) of the thermoplastic resin can be in the range of 0.3 g / 10 min to 80 g / 10 min under conditions of 190 ° C and a load of 2.16 kg. Also, 0.4 g / 10 min to 30 g / 10 min is preferable, and 0.5 g / 10 min to 20 g / 10 min is more preferable. It is even more preferable 3 g / 10 min to 15 g / 10 min, even more preferably 6 g / 10 min to 12 g / 10 min, and even more preferably 8 g / 10 min to 10 g / 10 min. When the MFR of the thermoplastic resin is 80 g / 10 min or less, crystallization during the stretching process is suppressed, resulting in good gripping properties against glass. When it is 30 g / 10 min or less, the gripping properties become even better, and when it is 10 g / 10 min or less, it tends to be even better.

[0035] When fiberizing thermoplastic resins, including those made using the spunbonding method, thermoplastic resins with a melt flow rate (MFR) of around 100 g / 10 min are often used due to the ease of forming threads in the melt. However, with such an MFR, thermoplastic resins, particularly biodegradable thermoplastic resins, often have weak thread strength during fiberization, making them prone to thread breakage during the stretching process. Therefore, an MFR of 15 g / 10 min or less tends to improve the strength of the single threads constituting the nonwoven fabric and prevent thread breakage during the stretching process. An MFR of 10 g / 10 min or less tends to improve thread breakage resistance. Furthermore, an MFR of 0.3 g / 10 min or more prevents the viscosity from becoming too high during melting, making it easier to form into threads. The MFR of a thermoplastic resin can be measured using the method described in the Examples below. The MFR of a thermoplastic resin can be adjusted by the type of thermoplastic resin, copolymer composition, molecular weight, melting point, etc.

[0036] The melting point of the thermoplastic resin is preferably 70°C to 200°C, more preferably 100°C to 170°C, and even more preferably 110°C to 130°C. If the melting point is below 70°C, the single yarn strength of the fibers constituting the nonwoven fabric decreases, making it more likely that yarn breakage will occur during the stretching process. On the other hand, if the melting point exceeds 200°C, the ratio of hard segments in the intramolecular structure becomes too high, resulting in a decrease in the grip of the glass protective material or nonwoven fabric on glass.

[0037] The thermoplastic resin may contain a copolymer. The copolymer content is preferably 50% by mass or more, more preferably 75% by mass or more, and even more preferably 90% by mass or more. When the thermoplastic resin contains the copolymer, the glass protective material can have good grip properties on glass.

[0038] In the present invention, from the viewpoints of biodegradability and environmental impact, it is preferable that the thermoplastic resin contains a biodegradable thermoplastic resin, and it is also possible for the thermoplastic resin to be composed solely of a biodegradable thermoplastic resin. Examples of biodegradable thermoplastic resins include polylactic acid, polylactic acid / polycaprolactone copolymers, polylactic acid / polyether copolymers, polyethylene terephthalate succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polyglycolic acid, polycaprolactone, polyvinyl alcohol, and cellulose acetate. Polyethylene terephthalate succinate and polybutylene adipate terephthalate-based aromatic polyesters are more preferred, with polybutylene adipate terephthalate-based resins being particularly preferred. When the biodegradable thermoplastic resin is an aromatic polyester, better stretchability can be obtained. When the biodegradable thermoplastic resin is a copolymer polyester containing structural units derived from an aromatic carboxylic acid component and an aliphatic carboxylic acid component, even better stretchability can be obtained.

[0039] When a polybutylene adipate terephthalate resin is contained as the thermoplastic resin, it may contain other thermoplastic resins as described above, or a biodegradable thermoplastic resin. For details on biodegradable thermoplastic resins, please refer to the positive list of GreenPla (plastic) classification number A-1 of the Japan BioPlastics Association. The fibers constituting the long-fiber nonwoven fabric of the present invention may contain a resin other than a thermoplastic resin. Examples of such resins include thermoplastic resins such as polyurethane and polyester.

[0040] The positive list (Ver. 2023.4 (Sep.)) of the Japan Bioplastics Association's GreenPla (plastic) classification number A-1 lists the following: hydroxyl-modified starch manufactured by Kuraray, starch polyesters Mater-Bi (registered trademark) NF01U and Mater-Bi (registered trademark) ZF03U / A manufactured by GSI Creos (Novamont), cellulose acetate (diacetate) manufactured by Daicel, and polylactic acid products NatureWorks 2000 series, 3000 series, 4000 series, 6000 series, 7000 series, 8000 series, Ingeo (registered trademark) 5061A, and Ingeo (registered trademark) 5061B manufactured by NatureWorks Japan. Further examples of polylactic acid include Kanepearl (registered trademark) B100 manufactured by Kaneka, Viroecole (registered trademark) BE-400, BE-410, and HYD-006 manufactured by Toyobo MC, REVODE (registered trademark) 100 series and 200 series manufactured by Daishin Yaoka (Zhejiang Haizheng Biomaterials), PLA manufactured by Chori (Pliith Biotechnology), and Luminy L-series, Luminy LX-series, and Luminy LX-series manufactured by Total Energies Corbion. Examples of suitable polylactic acid / polycaprolactone copolymers include Viroecole (registered trademark) BE-450, HYD-306, and BE-910 manufactured by Toyobo MC, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) includes AONILEX (registered trademark) manufactured by Kaneka, polyglycolic acid includes Cressage (registered trademark) and Credax (registered trademark) manufactured by Kureha, polylactic acid / polyether copolymers include Ecodia (registered trademark) L4E6 series manufactured by Toray, polycaprolactone includes Plaxel (registered trademark) H1P, H5C, and H8C manufactured by Daicel, and Capa (registered trademark) manufactured by Ingevity Japan. 6500, Capa 6500D, Capa 6800, Capa 6800D,Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) products include PHACT® A1000P and PHACT® S1000P manufactured by CJ Cheil Jedang, butanediol / long-chain dicarboxylic acid copolymers include Mater-Bi® CS series manufactured by GSI Creos (Novamont), polybutylene adipate / terephthalate is Ecoflex® manufactured by BASF Japan, aliphatic aromatic polyester is Ecoflex® FS manufactured by BASF Japan, polytetramethylene adipate-co-terephthalate is Origo-Bi ES01G manufactured by GSI Creos (Novamont), Eastar Bio, Ultra, and polybutylene succinate is BioPBS manufactured by PTT MCC. Examples of suitable PBS include BioPBS FZ71, BioPBS FZ91, BioPBS FZ78, TUNHE PBS manufactured by Blueridge, and ECO-B manufactured by Changchun Japan. Examples of polybutylene succinate adipate include BioPBS FD92 manufactured by PTT MCC, and examples of polybutylene adipate terephthalate include A400 (ECOPOND KD 1024) manufactured by KINGFA, TUNHE PBAT manufactured by BLUERIDGE, CKBP-PBAT-01 manufactured by Mitoku Harness, ECO-A manufactured by Changchun Japan, HF101 manufactured by HighChem (Zhejiang Huafeng Environmental Protection Materials), Ecoworld Biodegradable Polymer manufactured by JinHui ZhaoLong High Tech, and Biodegradable Resin manufactured by Kanghui New Material Technology. Examples of polyvinyl alcohols include KHB21, HF901 manufactured by Chori as polypropylene carbonate, Gohsenol (registered trademark), Gohsenex (registered trademark) T, Gohsenex (registered trademark) WO, and Nichigo (registered trademark) G Polymer manufactured by Mitsubishi Chemical, and Kuraray Poval (registered trademark) fully saponified product, Kuraray Poval (registered trademark) intermediate saponified product, Kuraray Poval (registered trademark) partially saponified product, Kuraray Poval (registered trademark) low saponified product, and Kuraray Exeval (registered trademark) manufactured by Kuraray.

[0041] As a monomer for synthesizing a thermoplastic resin, a biomass-derived monomer may be used. For biomass-derived monomers, reference may be made to the monomers listed in the positive list of classification number A (biomass plastics) of the Japan Bioplastics Association.

[0042] Polybutylene adipate terephthalate resin is a biodegradable resin, a copolymer of adipic acid, terephthalic acid, and butanediol. It is expected that polybutylene adipate terephthalate resin will provide a solution to waste disposal and microplastic problems. Adipic acid, terephthalic acid, and butanediol do not need to be copolymerized simultaneously; they may be copolymerized in multiple stages.

[0043] When synthesizing polybutylene adipate terephthalate resins, in addition to adipic acid, terephthalic acid, and butanediol, trace amounts of other copolymerization components may be added. Examples of other copolymerization components include dicarboxylic acids other than terephthalic acid and adipic acid, and modifiers for the purposes of chain extension, terminal blocking, etc. These may be used alone or in combination of two or more.

[0044] Other dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, etc. These may be used alone or in combination of two or more.

[0045] Examples of modifiers include polyisocyanate compounds and glycol compounds. Examples of polyisocyanate compounds include diisocyanate compounds. Examples of diisocyanate compounds include hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,5-naphthylene diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylene diisocyanate, carbodiimide-modified MDI, and polymethylenephenyl polyisocyanate. These compounds may be used alone or in combination of two or more. Examples of glycol compounds include diols other than butanediol and polyalkylene glycols. Examples of other diols include methanediol, ethanediol, propanediol, pentanediol, and hexanediol. Examples of polyalkylene glycols include polymethylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol (polytetramethylene glycol), etc. These may be used alone or in combination of two or more.

[0046] Examples of polybutylene adipate terephthalate resins include synthetic polymer compounds listed on the positive list of the Japan Bioplastics Association's GreenPla (plastic) classification number A-1. Specific examples include Ecoflex (registered trademark) manufactured by BASF Japan Ltd., EastarBio GP and Eastr Bo Ultra manufactured by GSI Creos Co., Ltd. (Novmont), A40 (ECP ONDKD1024) manufactured by KINGFA Co., Ltd., and TUNHEP BATTH-801T manufactured by XINJIANGBLUE RIDGETUNHECHEMICAL INDUSTRYJOINTSTOCK CO., LTD.

[0047] The total content of the adipic acid component, the terephthalic acid component, and the butanediol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 99 mol% or more, based on 100 mol% of all components constituting the thermoplastic resin. It is even more preferably 100 mol% of all components constituting the thermoplastic resin.

[0048] The nonwoven fabric is made of fibers containing a thermoplastic resin, preferably a biodegradable thermoplastic resin. That is, the fibers constituting the nonwoven fabric can contain other thermoplastic resins in addition to the biodegradable thermoplastic resin. The fibers constituting the nonwoven fabric preferably contain 80% by mass or more of the biodegradable thermoplastic resin, more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more, based on 100% by mass of the fibers constituting the nonwoven fabric.

[0049] The shape of the fibers constituting the nonwoven fabric is not particularly limited, but may have a round, flat, C-shaped, Y-shaped, V-shaped or other irregular cross section, and is preferably a round cross section. Furthermore, the fibers may have a sea-island structure, a sheath-core structure, or a split fiber structure.

[0050] The fibers constituting the nonwoven fabric preferably contain no more than 1% of flame retardants, inorganic fillers, softeners, plasticizers, pigments, antistatic agents, etc., in order to prevent transfer of components to the glass.

[0051] The fiber diameter of the fibers constituting the nonwoven fabric is preferably 5 μm to 60 μm, more preferably 10 μm to 50 μm, even more preferably 12 μm to 40 μm, and particularly preferably 16 μm to 30 μm. When the fiber diameter is 5 μm or more, spinnability in the spunbonding method is improved, enabling stable production. Furthermore, when the fiber diameter is 60 μm or less, unevenness of the nonwoven fabric is less likely to deteriorate, and when used as a glass protective material, local variations in impact absorption due to the amount of fiber can be reduced.

[0052] The basis weight of the nonwoven fabric is not particularly limited, but is preferably 10 to 200 g / m２ and can range from 15 to 150 g / m ２ and can range from 30 to 120 g / m ２ and can range from 55 to 100 g / m ２ However, since the cost of the protective material is high, the weight per unit area should be 120 g / m ２ It is desirable that the following:

[0053] The nonwoven fabric preferably has an apparent density of 0.4 g / cc or less, more preferably 0.35 g / cc or less, and even more preferably 0.3 g / cc or less. When the apparent density is 0.4 g / cc or less, the nonwoven fabric can absorb impacts when stacking glass sheets and storing or transporting them, thereby preventing the glass sheets from being damaged during storage or transport.

[0054] The apparent density is preferably 0.1 g / cc or more, more preferably 0.11 g / cc or more, even more preferably 0.13 g / cc or more, particularly preferably 0.15 g / cc or more, and even more preferably 0.2 g / cc or more. When the apparent density is 0.1 g / cc or more, even if friction occurs with glass when used as a glass protective material, the long-fiber nonwoven fabric is less susceptible to friction, and it is possible to prevent fibers from falling off from the long-fiber nonwoven fabric during use.

[0055] The nonwoven fabric preferably has a friction resistance against glass of 0.8 or more, more preferably 1.0 or more, even more preferably 1.5 or more, and even more preferably 2.0 or more. It can also be 7.0 or less, preferably 6.0 or less. When the friction resistance against glass is 1.0 or more, the grip on the glass is improved, and the protective material and the glass do not slip even when vibration is applied to the glass, preventing scratches on the glass surface due to rubbing. When the friction resistance against glass is 6.0 or less, the protective material on the glass surface can be removed smoothly without getting caught on the glass. In this specification, "a friction resistance against glass of 0.8 or more" means that any one side of the nonwoven fabric or foamed polyethylene sheet is designated as a first side, and the side opposite the first side is designated as a second side, and the friction resistance against glass of both the first side and the second side is 0.8 or more.

[0056] The thickness of the nonwoven fabric is preferably 0.2 mm or more, more preferably 0.22 mm or more. By making it 0.2 mm or more, the nonwoven fabric can absorb impact when stacking and storing or transporting glass, allowing the glass to be stored or transported without being damaged. Furthermore, the thickness is 0.8 mm or less, preferably 0.7 mm or less, more preferably 0.6 mm or less, even more preferably 0.55 mm or less, and particularly preferably 0.45 mm or less. By making the thickness 0.8 mm or less, the bulk of the protective material can be reduced when stacking and storing glass, allowing the load capacity to be increased.

[0057] It is preferable that the nonwoven fabric has not been subjected to a mechanical entanglement treatment. Examples of mechanical entanglement treatments include entanglement treatments by needle punching and water punching. Not being subjected to a mechanical entanglement treatment is preferable because it can be produced at low cost. It is also preferable because it can avoid the risk of needle contamination that can occur when using a needle punching method. In addition, the water punching method uses a large amount of water and requires a huge amount of energy. Therefore, from the perspective of environmental conservation and energy conservation, it is preferable that the nonwoven fabric has not been subjected to the mechanical entanglement treatment.

[0058] The nonwoven fabric may have a stress at 5% elongation of 0.1 to 100 (N / 2.5 cm), preferably 0.3 to 2.0 (N / 2.5 cm). In this specification, "a stress at 5% elongation of 0.1 (N / 2.5 cm) or more" means that the stress at 5% elongation in the MD (machine direction) direction is 0.1 (N / 2.5 cm) or more and the stress at 5% elongation in the CD (cross direction) direction is 0.1 (N / 2.5 cm) or more.

[0059] The nonwoven fabric can have a mechanical strength of 1 to 200 (N / 2.5 cm), preferably 5 to 100 (N / 2.5 cm). In particular, a mechanical strength of 8 (N / 2.5 cm) or more can prevent the fabric from easily breaking when used as a glass protection material. In this specification, "a mechanical strength of 1 (N / 2.5 cm) or more" means that the mechanical strength in the MD (machine direction) direction is 1 (N / 2.5 cm) or more and the mechanical strength in the CD (cross direction) direction is 1 (N / 2.5 cm) or more.

[0060] The nonwoven fabric preferably has an elongation of 50% or more, more preferably 60% or more, even more preferably 70% or more, and even more preferably 100% or more. When the elongation is 50% or more, when used as a glass protection material, it does not tear even when lightly pulled and easily deforms, providing sufficient conformability for its intended use. Furthermore, the elongation is preferably 500% or less, more preferably 300% or less. In this specification, "elongation of 50% or more" means that the elongation in the MD (machine direction) direction is 50% or more and the elongation in the CD (cross direction) direction is 50% or more. To improve the elongation of the nonwoven fabric, it is effective to use a thermoplastic resin with a relatively small melt flow rate (MFR) and to adopt preferred manufacturing conditions according to its melting characteristics.

[0061] The nonwoven fabric can have a bending resistance of 5 to 150, preferably 10 to 100, more preferably 12 to 80, and even more preferably 13 to 50. In particular, when the bending resistance is 13 or more, the amount of sagging when cantilevered is small, and the handling of the nonwoven fabric when laid between glass plates is improved. Furthermore, when the bending resistance is 100 or less, the impact absorption is good, and when it is 50 or less, the impact absorption tends to be even better.

[0062] The impact absorption can be evaluated by dividing the bending resistance by the basis weight using the following formula, where the bending resistance corresponds to the amount of resin per unit area as an index: Impact absorption = bending resistance (-) / basis weight (g / m ２ In the present invention, from the viewpoint of obtaining good impact absorption properties despite a thin thickness, the impact absorption value calculated by this calculation formula is preferably 1.0 or less, more preferably 0.9 or less, and even more preferably 0.7 or less.

[0063] The apparent density of the glass protective material is preferably 0.4 g / cc or less, more preferably 0.35 g / cc or less, and even more preferably 0.3 g / cc or less. An apparent density of 0.4 g / cc or less can absorb impacts when stacking glass sheets and storing or transporting them, preventing the glass from being damaged during storage or transport. The apparent density is also preferably 0.1 g / cc or more, more preferably 0.11 g / cc or more, even more preferably 0.13 g / cc or more, particularly preferably 0.15 g / cc or more, and even more preferably 0.2 g / cc or more. When the apparent density is 0.1 g / cc or more, the glass protective material is less susceptible to friction even when rubbed against glass, and can prevent fibers from falling off from the long-fiber nonwoven fabric during use.

[0064] The glass protective material has a friction resistance against glass of 0.8 or more, preferably 1.0 or more, more preferably 1.5 or more, and even more preferably 2.0 or more. It can also be 7.0 or less, preferably 6.0 or less. When the friction resistance against glass is 1.0 or more, the grip on the glass is improved, and the protective material and the glass do not slip even when vibration is applied to the glass, preventing scratches on the glass surface due to rubbing. When the friction resistance against glass is 6.0 or less, the protective material can be removed smoothly without getting caught on the glass when removed from the glass surface. In this specification, "a friction resistance against glass of 0.8 or more" means that any one side of a nonwoven fabric or foamed polyethylene sheet is designated as a first side, and the side opposite the first side is designated as a second side, and the friction resistance against glass of both the first side and the second side is 0.8 or more.

[0065] The glass protective material preferably has a glass protection rating of 10 or less, more preferably 9 or less, even more preferably 8 or less, particularly preferably 7 or less, and most preferably 6 or less. By setting the glass protection rating to 10 or less, the bulk of the protective material can be reduced when stacking and storing glass, allowing for an increased load capacity, and also making it possible to prevent scratches on the glass surface due to rubbing or impacts during glass transportation.

[0066] Here, the glass protection property is a value calculated by the following formula, which is obtained by multiplying the apparent density by the bending resistance and dividing the product by the friction resistance value against glass (average value of the first and second surfaces): Glass protection property = apparent density (g / cc) × bending resistance (-) / friction resistance value (-)

[0067] The glass protective material has a thickness of 0.2 mm or more, preferably 0.22 mm or more. By making the thickness 0.2 mm or more, the nonwoven fabric absorbs impact when stacking and storing or transporting glass, allowing the glass to be stored or transported without being damaged. Furthermore, the thickness is 0.8 mm or less, preferably 0.7 mm or less, more preferably 0.6 mm or less, even more preferably 0.55 mm or less, and particularly preferably 0.45 mm or less. By making the thickness 0.8 mm or less, the bulk of the protective material is reduced when stacking and storing glass, allowing for an increased load capacity.

[0068] The glass protective material includes a long-fiber nonwoven fabric. The glass protective material may contain other materials than the long-fiber nonwoven fabric, but when it is composed only of the long-fiber nonwoven fabric, it is particularly preferably used as an interleaf for glass plates. The glass protective material is useful when sandwiched between two pieces of glass, and the long-fiber nonwoven fabric is useful for protecting glass. The volume ratio of the long-fiber nonwoven fabric in the glass protective material can be 50% or more, more preferably 60% or more, even more preferably 70% or more, even more preferably 80% or more, even more preferably 90% or more, even more preferably 95% or more, and even more preferably 100%.

[0069] The method for producing the nonwoven fabric is not limited, and known methods such as spunbonding, meltblowing, airlaid, carding, and papermaking can be used. The nonwoven fabric of this embodiment is preferably integrated by bonding, and bonding methods such as embossing and thermal bonding can be used. A long-fiber nonwoven fabric is preferred, and it is more preferred to produce it by the spunbonding method, as this can be produced efficiently and can suppress fluffing after molding.

[0070] When using the spunbonding method, a resin is heated and melted and extruded from a spinneret. The resulting spun yarn is cooled using a known cooling device and pulled and attenuated using a suction device such as an air sucker. The yarn group discharged from the suction device is then opened and deposited on a conveyor to form a web. The web formed on the conveyor is then partially thermocompressed using a partial thermocompression device such as a heated embossing roll, thereby obtaining a spunbonded nonwoven fabric. Nonwoven fabrics obtained by the spunbonding method have characteristic physical properties such as high fabric strength and no shedding of short fibers due to breakage of bonded portions, and are also low-cost and highly productive.

[0071] A nonwoven fabric can be produced, for example, by a production method including the following steps A to C. A nonwoven fabric is obtained through step A in which a molten thermoplastic resin is discharged from a spinneret, cooled to solidify, and then pulled and stretched by an ejector to form fibers, step B in which the long fibers obtained in step A are collected to form a long-fiber web, and step C in which the long-fiber web is thermocompression bonded. <Step A> In the production method for a nonwoven fabric according to this embodiment, first, a molten thermoplastic resin is discharged from a spinneret, cooled to solidify, and then pulled and stretched by an ejector to form fibers.

[0072] This step A can be carried out using a spinning machine such as a conventionally known spunbond spinning machine.

[0073] In the step A, the mixture is spun from a spinneret having an orifice diameter of 0.1 to 0.5 mm, and fed to an ejector at a pressure of 0.5 to 4.0 kg / cm ２It is preferable to supply dry air at a pressure (jet pressure) of 0.15 to 0.5 mm and stretch the fibers. The orifice diameter of the spinneret is more preferably 0.15 to 0.5 mm, and even more preferably 0.18 to 0.45 mm. Controlling the orifice diameter within the above range facilitates control of the fiber diameter. Furthermore, controlling the supply pressure (jet pressure) of the dry air within the above range facilitates constant control of the spinning speed and allows for appropriate drying. <Step B> Next, the long fibers obtained in step A are collected to form a long-fiber web (step B). For example, the long fibers may be collected while being spread on a conveyor below to form a long-fiber web. <Step C> Next, the long-fiber web obtained in step B is thermocompression-bonded (step C). The pre-compression bonding is performed within a temperature range in which the long-fiber web does not shrink. This allows for suitable transport. The temperature during the temporary pressure bonding is preferably at least 10°C lower than the melting point of the resin of the nonwoven fabric, the linear pressure is preferably 5 to 100 N / mm, more preferably 20 to 80 N / mm, and the pressure-bonded area ratio is preferably 3 to 50%, more preferably 6 to 40%. By performing the pressure bonding within an appropriate range, it is possible to achieve both flexibility and stretchability of the nonwoven fabric and pressure bonding.

[0074] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0075] The properties such as physical properties in the present invention are specifically measured based on the following methods.

[0076] (Intrinsic Viscosity) 0.1 g of resin was weighed and dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (60 / 40 (weight ratio)). The viscosity was measured three times at 30° C. using an Ostwald viscometer, and the average value was calculated.

[0077] (Specific gravity) A density gradient solution was prepared using calcium nitrate tetrahydrate in a density gradient tube. ３ Using a specific gravity float range of 100%, the fiber after jet drawing was put into a density gradient tube, and after stabilizing for 4 hours or more, the scale at the floating position was read, and the specific gravity was calculated from the float calibration curve.

[0078] (Crystalline Melting Enthalpy) 2.0 mg ± 0.1 mg of resin was weighed, and the endothermic curve was measured using a TA Instruments Discovery DSC25 differential scanning calorimeter at a heating rate of 20 ° C. / min under a nitrogen atmosphere. The crystalline melting enthalpy (J / g) was determined from the integrated value of the endothermic peak (melting peak). Specifically, the integrated value of the endothermic peak (melting peak) was determined by taking the point where the curve relating to the endothermic peak (melting peak) begins to depart from the low-temperature baseline as the starting point and the point where it begins to contact the high-temperature baseline as the end point, drawing a straight line connecting the starting point and the end point, and integrating the area enclosed by the straight line and the curve. This operation was performed three times to determine the average value (n = 3) of the crystalline melting enthalpy. The starting point was also designated as the melting onset temperature (° C.).

[0079] (Melting Point) The resin was weighed to a mass of 2.0 mg ± 0.1 mg. Next, a differential scanning calorimeter (TA Instruments, Discovery DSC25) was used to measure the DSC curve under a nitrogen atmosphere at a heating rate of 20°C / min. The endothermic peak (melting peak) temperature was determined from the DSC curve. The above operation was repeated three times, and the average melting point (n = 3) was calculated.

[0080] (Melt Flow Rate (MFR)) After the resin was vacuum dried at 80°C for 2 hours or more, the melt flow rate (MFR) was quickly measured so as to minimize the incorporation of moisture from the air. The melt flow rate was measured in accordance with ISO 1133 using a Melt Indexer F-F01 machine manufactured by Toyo Seiki Seisaku-sho, Ltd. The measurement temperature was 190°C and the load was 2.16 kg. This operation was performed three times to determine the average melt flow rate (n = 3).

[0081] (Weight-average molecular weight) The resin was dissolved in a small amount of chloroform to prepare a sample solution. The sample solution was further diluted with chloroform to prepare a sample solution concentration of 0.05% by mass. The solution was filtered through a 0.2 μm membrane filter, and GPC analysis of the obtained solution was performed under the following conditions. The molecular weight was calculated in terms of standard polystyrene.

[0082] Apparatus: TOSOH HLC-8320GPC Column: TSKgel Super HM-H x 2 + TSKgel Super H2000 (TOSOH) Solvent: Chloroform

[0083] (Weight per unit area) The mass per unit area was measured in accordance with JIS L1913 (2010) 6.2.

[0084] (Thickness) The thickness was measured in accordance with JIS L1913 (2010) 6.1.

[0085] (Apparent density (bulk density)) 1 cm from the above basis weight and thickness obtained in accordance with JIS-L1913 (2010) 6.2 and 6.1 ３ The weight per unit was converted to the bulk density. ２ The thickness was measured using a terminal, and the bulk density was calculated by dividing the basis weight by the thickness.

[0086] (Fiber Diameter) Five randomly selected points on the sample (long fiber web before temporary bonding) were used to measure the diameter of single fibers (n=20) using an optical microscope, and the average value was calculated.

[0087] (Fineness (dtex)) Five randomly selected points on the sample (long fiber web before pre-bonding) were used to measure the single fiber diameter (n = 20) using an optical microscope to determine the average single fiber diameter. Fibers were taken out from the same five points, and the specific gravity of the fibers (n = 5) was measured using a density gradient tube to determine the average specific gravity. Next, the fineness [dtex], which is the fiber weight per 10,000 m, was determined from the single fiber cross-sectional area and average specific gravity calculated from the average single fiber diameter.

[0088] (Spinning Speed ​​(m / min)) The spinning speed V (m / min) was calculated from the above-mentioned fineness T (dtex) and the set single-hole output rate Q (g / min) according to the following formula: V = (10000 x Q) / T

[0089] (Stress at 5% Elongation) A 25 x 100 mm sample (nonwoven fabric sheet) was prepared. Using a constant-speed extension tensile tester with a self-recording device, the sample was attached to a grip spacing of 50 mm while being pulled by hand to the extent that it would not loosen, and an initial load of 0.02 N / 25 mm was applied. The sample was then stretched to 5% of the grip spacing at a tensile speed of 10 mm / min. The load value at this time was determined as the stress at 5% elongation. Measurements were performed with n = 5 in each of the longitudinal and transverse directions, and the average value was rounded to the nearest tenth.

[0090] (Mechanical Strength) A 25 x 100 mm sample (nonwoven fabric sheet) was prepared. Using a constant-speed extension tensile tester with a self-recording device, the sample was attached with a grip distance of 50 mm while being pulled by hand to the extent that it would not loosen, and an initial load of 0.02 N / 25 mm was applied. The sample was then stretched at a tensile speed of 10 mm / min until it broke. The maximum load value at this time was determined as the mechanical strength. Measurements were performed with n = 5 in each of the longitudinal and transverse directions, and the average value was rounded to the nearest tenth.

[0091] (Elongation) A 25 x 100 mm sample (nonwoven fabric sheet) was prepared. Using a constant-speed extension tensile tester with a self-recording device, the sample was attached with a grip distance of 50 mm while being pulled by hand to the extent that it would not loosen, and the initial load was set to 0.02 N / 25 mm. The sample was then stretched at a tensile speed of 10 mm / min until it broke. The maximum elongation value at this time was calculated as the average elongation. Measurements were performed with n = 5 in each of the longitudinal and transverse directions, and the average value was rounded to the nearest tenth.

[0092] (Bending Resistance) The bending resistance per unit area was measured according to JIS L1913 (2000) 6.7.3 (cantilever method).

[0093] (Impact Absorbency) The value obtained by dividing the bending resistance by the basis weight using the following formula was used to evaluate the impact absorbency, using the bending resistance corresponding to the amount of resin per unit area as an index: Impact absorbency = bending resistance (-) / basis weight (g / m ２ )

[0094] (Yarn Breakage Resistance) In step A, the yarn state during drawing was visually checked, and the yarn breakage resistance was evaluated by judging the number of yarn breaks per 5 minutes as follows: ◯: 1 yarn / 5 min or less △: 2 to 9 yarns / 5 min or less ×: 10 yarns / 5 min or more

[0095] (Frictional Resistance Value Against Glass) A 12 x 500 mm sample (nonwoven fabric sheet or foamed polyethylene sheet) was prepared. The sample was attached to the contact (approximately 1 cm square) of a KES-SE friction tester (manufactured by Kato Tech). A plate glass (manufactured by Matsunami Glass Industry Co., Ltd., model S1112) was placed on the sample stage, and the surface of the test piece was scanned 30 mm with the contact under a load of 50 gf in an environment of 20°C and 65% humidity to measure the average coefficient of friction. Measurements were made on both sides of the nonwoven fabric (n = 5 each), and the average value was rounded to the nearest tenth.

[0096] (Glass protection ability) The glass protection ability was evaluated by multiplying the apparent density by the bending resistance and dividing the result by the friction resistance value against glass (average value of the first and second surfaces) using the following formula: Glass protection ability = apparent density (g / cc) × bending resistance (-) / friction resistance value (-)

[0097] (Grip Property) A sample (nonwoven fabric sheet or foamed polyethylene sheet) measuring 170 mm in length and 60 mm in width was prepared. A table with a 45-degree slope was prepared, and the nonwoven fabric was attached to the slope. A ruler was attached to indicate the length of the slope, with the top of the slope being 0 cm. A 26 x 76 mm, approximately 1.0 mm thick glass plate (manufactured by Matsunami Glass Industry Co., Ltd., model S1112) was prepared. The short side of the glass plate was placed at the top of the slope, i.e., the 0 cm position on the ruler, in an environment of 20°C and 65% humidity. The distance the glass slid down on each side of the nonwoven fabric in 10 seconds was measured, and the grip property was evaluated as follows. In this specification, "both sides" refers to any one side of the nonwoven fabric sheet or foamed polyethylene sheet as the first side, and the side opposite the first side as the second side, with the first and second sides collectively referred to as "both sides." ◎: Within 0.3 mm ○: More than 0.3 mm, ×: Within 9 mm

[0098] (Biodegradability) It was determined whether the resin that makes up the nonwoven fabric sheet retained biodegradable properties. ◯: The substance name (resin name) is listed on the Japan Bioplastics Association's positive list for GreenPla (biodegradable plastic) classification number A-1. ×: The substance name (resin name) is not listed on the Japan Bioplastics Association's positive list for GreenPla (biodegradable plastic) classification number A-1.

[0099] (Overall evaluation) An overall evaluation was made based on the above evaluations. ⊚: Thin, has good shock absorption, and has excellent grip properties (friction resistance, grip), making it an excellent glass protective material. ◯: Thin, has sufficient shock absorption and grip properties, and can be used well as a glass protective material. ×: Too thick, with a poor balance between thickness and shock absorption, etc., and does not have sufficient grip properties, making it unsuitable for practical use as a glass protective material.

[0100] Example 1 Polybutylene adipate terephthalate (MFR: 9 g / min, melting point: 120°C, crystalline melting enthalpy: 14 J / g) (abbreviated as PBAT) shown in Table 1 was melted and kneaded in a single-screw extruder, and extruded by a spunbond method at a throughput rate of 0.5 g / min / Hole and a spinning temperature of 230°C. A group of filaments was pulled by a high-speed airflow pulling device using an air jet (Step A), and these were deposited on a moving collecting surface to prepare a long-fiber web (circular cross section) (Step B).

[0101] Next, using a pair of embossing rolls consisting of a roll having a concave-convex pattern on its surface and a roll having a smooth surface, the fibers were heat-pressed under the conditions of a pressure-bonding area ratio of 12%, a temperature of 80°C for both rolls, and a roll linear pressure of 40 N / mm (step C), resulting in a fiber diameter of 21 μm and a basis weight of 70 g / m ２ A nonwoven fabric sheet serving as a glass protection material was obtained.

[0102] (Example 2) A PBAT resin (MFR: 20 g / min, melting point: 120°C, crystalline melting enthalpy: 18 J / g) was used, and a spinning speed was adjusted to 1500 m / min. The same procedure as in Example 1 was repeated to produce a woven fabric having a fiber diameter of 18 μm and a basis weight of 70 g / m. ２ We have manufactured a nonwoven fabric sheet that is a glass protection material.

[0103] Example 3 Copolymer polyethylene (abbreviated as coPE) (UMERIT 613A, ethylene-1-hexene copolymer, MFR: 30 g / min, melting point: 110°C, manufactured by Ube Maruzen Polyethylene Co., Ltd.) was melted and kneaded in a single-screw extruder, and extruded by a spunbond method at a throughput rate of 0.5 g / min / hole and a spinning temperature of 190°C. A group of filaments was pulled by a high-speed air jet pulling device and deposited on a moving collecting surface to prepare a long-fiber web.

[0104] Next, using a pair of embossing rolls consisting of a roll with a concave-convex pattern on the surface and a roll with a smooth surface, the fabric was heat-pressed under the conditions of a pressure-bonding area ratio of 12%, a temperature of 100°C for both rolls, and a roll linear pressure of 30 N / mm, to obtain a fiber diameter of 20 μm and a basis weight of 50 g / m. ２ A nonwoven fabric sheet serving as a glass protection material was obtained.

[0105] Comparative Example 1 Polyethylene terephthalate (intrinsic viscosity (iv value): 0.63) (abbreviated as PET) was melted and kneaded in a single-screw extruder, and extruded by a spunbond method at a throughput rate of 0.7 g / min / Hole and a spinning temperature of 280°C. A group of filaments was pulled by a high-speed air jet pulling device and deposited on a moving collecting surface to prepare a long-fiber web.

[0106] Next, using a pair of embossing rolls consisting of a roll with a concave-convex pattern on the surface and a roll with a smooth surface, the fabric was heat-pressed under the conditions of a pressure-bonding area ratio of 12%, a temperature of 240°C for both rolls, and a roll linear pressure of 30 N / mm, to obtain a fiber diameter of 12 μm and a basis weight of 50 g / m ２ A nonwoven fabric sheet of 1000g was obtained.

[0107] Comparative Example 2 Polyethylene terephthalate (intrinsic viscosity (iv value): 0.63) (abbreviated as PET) was melted and kneaded in a single-screw extruder, and extruded by a spunbond method at a throughput rate of 0.7 g / min / Hole and a spinning temperature of 280°C. A group of filaments was pulled by a high-speed air jet pulling device and deposited on a moving collecting surface to prepare a long-fiber web.

[0108] Next, using a pair of embossing rolls consisting of a roll with a concave-convex pattern on the surface and a roll with a smooth surface, the fabric was heat-pressed under the conditions of a pressure-bonding area ratio of 12%, a temperature of 180°C for both rolls, and a roll linear pressure of 30 N / mm, to obtain a fiber diameter of 15 μm and a basis weight of 50 g / m ２ A nonwoven fabric sheet of 1000g was obtained.

[0109] The resulting nonwoven fabric sheet was then spun using a 40-count needle manufactured by Foster at a needle density of 64 needles / cm ２ , needle punched at a needle depth of 9 mm, with a basis weight of 50 g / m ２ A long fiber nonwoven fabric sheet was obtained.

[0110] Comparative Example 3 For comparison, a similar test was carried out on a foamed polyethylene sheet (trade name "Miramat") that is generally used as a glass protection material.

[0111] Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0112]

[0113] As shown in the results in Table 1, in Examples 1 to 3, the long-fiber nonwoven fabrics obtained using thermoplastic resins with specific melting properties had higher friction resistance values, and glass protective materials were obtained that had excellent gripping properties on glass and had impact absorption properties despite their thin thickness. In particular, in Examples 1 and 2, such glass protective materials were provided using biodegradable long-fiber nonwoven fabrics.

[0114] In contrast, in Comparative Examples 1 and 2, the MFR was greater than the predetermined range, which promoted crystallization, resulting in a lower friction resistance of the long-fiber nonwoven fabric, a decrease in gripping ability, and insufficient shock absorption. In Comparative Example 3, the foamed sheet was thick, resulting in a poor balance between thickness and shock absorption.

Claims

1. A glass protection material containing a long-fiber nonwoven fabric, the long-fiber nonwoven fabric being composed of fibers containing a thermoplastic resin, the thermoplastic resin having a melt flow rate (MFR) of 0.3 to 80 g / 10 min at 190°C under a load of 2.16 kg, a thickness of 0.2 mm to 0.8 mm, and a friction resistance against glass of 0.8 or more.

2. The glass protecting material according to claim 1, characterized in that the apparent density is 0.4 g / cc or less.

3. A glass protection material as described in claim 1 or 2, characterized in that the thermoplastic resin is one or more copolymers selected from polyamide-based resins, polystyrene-based resins, polyolefin-based resins, polyacetal-based resins, polycarbonate-based resins, polyvinyl chloride-based resins, AS resins, ABS resins, acrylic resins, polyester-based resins, polyvinyl alcohol-based resins, vinylidene chloride-based resins, and polyether-based resins.

4. A glass protection material according to claim 1 or 2, wherein the thermoplastic resin is a polyester resin.

5. A glass protection material according to claim 1 or 2, characterized in that the thermoplastic resin is an aromatic-containing polyester.

6. A glass protecting material according to claim 1 or 2, wherein the thermoplastic resin has a butylene skeleton.

7. A glass protection material as described in claim 1 or 2, characterized in that the thermoplastic resin contains adipic acid components, terephthalic acid components, and butanediol components in a total amount of 70 mol% or more out of 100 mol% of all components.

8. A glass protection material according to claim 1 or 2, characterized in that the melting point of the thermoplastic resin is in the range of 70°C or higher and 200°C or lower.

9. The glass protection material according to claim 1 or 2, wherein the thermoplastic resin contains a biodegradable resin.

10. The glass protection material according to claim 7, wherein the biodegradable resin is polybutylene adipate terephthalate.

11. The glass protection material according to claim 1 or 2, characterized in that it has not been subjected to a mechanical entanglement treatment.

12. A method for producing a long-fiber nonwoven fabric contained in the glass protective material according to claim 1 or 2, comprising: step A of discharging molten thermoplastic resin from a spinneret, cooling and solidifying it, and then pulling and stretching it with an ejector to form long fibers; step B of collecting the long fibers obtained in step A to form a long-fiber web; and step C of pre-heat-pressing the long-fiber web.

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