JP7653084B2 - Preforms and bottles - Google Patents

Description

The present invention relates to a preform and a bottle obtained by blow molding the preform.

Polyesters such as polyethylene terephthalate are widely used in the manufacture of bottles for filling beverages and other products because they are inexpensive and have excellent mechanical properties, chemical stability, heat resistance, gas barrier properties, and transparency. In particular, there is a demand for the development of bottles with higher gas barrier properties to maintain the quality of the contents.

Various gas barrier materials that prevent the permeation of oxygen and other gases have been known, and bottles equipped with layers containing these have been proposed. Examples of gas barrier materials that are known include nylon resin, polyvinyl alcohol, ethylene-vinyl acetate copolymer, and polyacrylonitrile resin.

In addition, bottles have been proposed that have improved gas barrier properties by providing a vapor deposition film of inorganic oxides such as silicon oxide or aluminum oxide, or a vapor deposition film of an inorganic material such as aluminum. For example, Patent Documents 1 and 2 propose plastic bottles that are provided with a vapor deposition film of an inorganic oxide to improve gas barrier properties.

JP 2001-301731 A JP 2007-223098 A

In recent years, attempts have been made to recycle used bottles in order to reduce the burden on the environment. However, because it is difficult to separate the layer containing the gas barrier material from a bottle having such a layer, bottles having such a layer are not well suited for recycling, and improvements are required.

In addition, vapor-deposited films of inorganic substances and inorganic oxides have poor stretchability and cannot follow the stretching caused by blow molding of the preform, resulting in cracks and other defects that reduce the gas barrier properties. Therefore, in the case of bottles such as those described in References 1 and 2, a vapor-deposited film must be formed on the bottle obtained by blow molding the preform.

However, from the viewpoint of bottle productivity, it is more desirable to impart gas barrier properties to a preform or the like before molding the bottle, and then blow mold this to produce a bottle. In addition, since there is no need to form a vapor deposition film on the bottle, there is no need to prepare a separate device at the delivery destination of the preform, and furthermore, since it is possible to transport the preform in its preform state, costs can be reduced. For these reasons, there is a demand for a preform that has high gas barrier properties and can maintain its high gas barrier properties even after blow molding.

An object of the present invention is to provide a preform that is excellent in recyclability and gas barrier property after blow molding.
Another object of the present invention is to provide a bottle obtained by blow molding the preform.

The present invention provides a preform comprising a support and a barrier layer,
the support comprises polyester;
The preform has a barrier layer including a carboxy-containing resin and a polyvinyl alcohol-based resin.

In the preform, the carboxyl group-containing resin may contain polyacrylic acid.

In the preform, the content of the carboxyl group-containing resin may be 1% by mass or more and 80% by mass or less based on all components contained in the barrier layer.

In the preform, the mass ratio of the carboxyl group-containing resin to the polyvinyl alcohol resin may be 1/20 or more and 10/1 or less.

In the preform, the thickness of the barrier layer of the preform may be 2.0 μm or more and 1000.0 μm or less.

The present invention is a bottle obtained by blow molding the above preform.

The bottle may have a volume increase rate of 2 to 45 times that of the preform.

In the bottle, the thickness of the barrier layer of the bottle may be 0.1 μm or more and 200.0 μm or less.

The oxygen permeability of the bottle may be 0.100 cc/day/bottle/0.21 atm or less.

According to the present invention, a preform having excellent recyclability and gas barrier properties after blow molding can be provided.
Furthermore, according to the present invention, it is possible to provide a bottle obtained by blow molding the preform.

FIG. 1 is a schematic half-sectional view showing one embodiment of a preform of the present invention. FIG. 1 is a schematic half-sectional view showing one embodiment of a preform of the present invention. FIG. 1 is a schematic half-sectional view showing one embodiment of a bottle of the present invention. FIG. 1 is a schematic half-sectional view showing one embodiment of a bottle of the present invention.

<Preform>
The preform of the present invention includes a support and a barrier layer. Since the preform of the present invention has excellent gas barrier properties even after blow molding, it can be suitably used as a preform for a bottle to be blow molded.

Figure 1 is a schematic half-sectional view showing one embodiment of the preform of the present invention. As shown in Figure 1, the preform 10 has a mouth portion 11, a body portion 12 connected to the mouth portion 11, and a bottom portion 13 connected to the body portion 12. Of these, the mouth portion 11 corresponds to the mouth portion 21 of the bottle 20 described below, and has approximately the same shape as the mouth portion 21. The body portion 12 corresponds to the neck portion 22, shoulder portion 23, and body portion 24 of the bottle 20, and has an approximately cylindrical shape. The bottom portion 13 corresponds to the bottom portion 25 of the bottle 20, and has an approximately hemispherical shape.

The mouth 11 includes a threaded portion 14 that corresponds to a threaded portion 26 of the bottle 20 described below to which a cap (not shown) is screwed, a cap 15 that is provided below the threaded portion 14 and corresponds to a cap 27 of the bottle 20, and a support ring 16 that is provided below the cap 15 and corresponds to a support ring 28 of the bottle 20. The shape of the mouth 11 may be a conventionally known shape.
In this specification, "upper" and "lower" refer to the upper and lower sides, respectively, of a bottle 20 (described later) in an upright position (FIGS. 3 and 4).

As shown in Fig. 1, the preform 10 includes a support 17 and a barrier layer 18. As shown in Fig. 1, the mouth portion 11 is formed of the support 17, and the body portion 12 and the bottom portion 13 are formed of the support 17 and the barrier layer 18. As shown in Fig. 1, the barrier layer 18 is provided on the outside of the preform 10 so as to surround the preform 10.
The barrier layer 18 may be provided over the entire or partial area of the body portion 12 and/or bottom portion 13 (not shown).
The barrier layer 18 may be provided on the inside of the preform 10 or may be provided between the support 17 and other layers (not shown).

In one embodiment, as shown in FIG. 2, when the lower end of the mouth portion 11 is "0L" and the lower end of the bottom portion 13 is "1L", the preform has a barrier layer 18 over the entire outer area of at least 0.4L to 0.6L. This makes it possible to efficiently improve the gas barrier properties of the bottle obtained from the preform. It is preferable that the preform has a barrier layer over the entire outer area of at least 0.2L to 0.7L, and it is more preferable that the barrier layer is over the entire outer area of at least 0.1L to 0.9L.

The preform 10 of the present invention may be provided with a protective layer on the inside and/or outside of the barrier layer 18 (not shown).

The cross-sectional thickness of the preform is preferably 1.4 mm or more and 4.5 mm or less, and more preferably 2.0 mm or more and 3.0 mm or less.
The cross-sectional thickness of the preform can be measured, for example, at the body portion of the preform having at least the support and the barrier layer, and means the location where the cross-sectional thickness is the thinnest.

The preform of the present invention may be printed. The image formed by printing is not particularly limited, and examples thereof include patterns and letters. From the viewpoint of not being affected by the color tone of the preform, it is preferable that the printing is applied to the outer surface of the preform.
Printing can be carried out by a known method, such as an inkjet method, a gravure printing method, an offset printing method, a flexographic printing method, a thermal transfer method, a silk screen method, a pad method, a hot stamp method, and a cold stamp method.

The preform's support, barrier layer, and protective layer are described below.

(Support)
In the preform of the present invention, the support contains polyester, which allows the preform to be well blow molded and improves the gas barrier properties of the bottle.
From the viewpoint of the recyclability of the bottle, the support of the preform preferably has a polyester content of 90% by mass or more, more preferably 97% by mass or more, and further preferably is made of polyester.

In the present invention, the term "polyester" refers to a polymer formed by ester bonds. Such a polyester is usually obtained by polycondensation of a dicarboxylic acid compound and a diol compound.
Examples of the dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosanedioic acid, pimelic acid, azelaic acid, methylmalonic acid, ethylmalonic acid, adamantanedicarboxylic acid, norbornenedicarboxylic acid, cyclohexanedicarboxylic acid, decalindicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 5-sodiumsulfoisophthalic acid, phenylendanedicarboxylic acid, anthracenedicarboxylic acid, phenanthrenedicarboxylic acid, 9,9'-bis(4-carboxyphenyl)fluorene acid, and ester derivatives thereof.
Examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, 2-methyl-1,3-propanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, cyclohexanediethanol, decahydronaphthalenedimethanol, decahydronaphthalenediethanol, norbornanedimethanol, norbornanediethanol, tricyclodecanedimethanol, tricyclodecaneethanol, tetracyclododecanedimethanol, tetracyclododecanediethanol, decalindimethanol, decalindiethanol, and 5-methylol-5-ethyl 2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane, cyclohexanediol, bicyclohexyl-4,4'-diol, 2,2-bis(4-hydroxycyclohexylpropane), 2,2-bis(4-(2-hydroxyethoxy)cyclohexyl)propane, cyclopentanediol, 3-methyl-1,2-cyclopentadiol, 4-cyclopentene-1,3-diol, adamantanediol, paraxylene glycol, bisphenol A, bisphenol S, styrene glycol, trimethylolpropane, pentaerythritol, and bis-β-hydroxyethyl terephthalate (BHET).
The polyester is preferably polyethylene terephthalate or a modified polyethylene terephthalate obtained by polymerizing a raw material monomer of polyethylene terephthalate with a copolymerizable monomer.

The support of the preform may contain a resin other than polyester, as long as the characteristics of the present invention are not impaired. Examples of the resin include polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylic resin, polyamide, polyacetal, and polycarbonate. These resins can be used alone or in combination of two or more.
From the viewpoint of the recyclability of the bottle, the content of these resins is preferably less than 10% by mass, and more preferably less than 3% by mass.

The support of the preform may contain additives to the extent that the characteristics of the present invention are not impaired. Examples of additives include oxygen absorbers, plasticizers, UV stabilizers, antioxidants, coloring inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and colorants. These additives may be used alone or in combination of two or more.

The support of the preform may have a single layer structure or a multi-layer structure of two or more layers. In addition, when the support has a multi-layer structure, each layer may have the same composition or different compositions.

The cross-sectional thickness of the support of the preform is preferably 1.3 mm or more and 4.3 mm or less, and more preferably 1.9 mm or more and 2.9 mm or less.
The cross-sectional thickness of the support of the preform can be measured at the body of the preform, and refers to the location where the cross-sectional thickness is the thinnest.

It is preferable to subject the support of the preform to a surface treatment. Examples of surface treatments include corona treatment, low-temperature plasma treatment, and flame treatment. By subjecting the support to such a surface treatment, the wettability of the support surface is improved, and the adhesion between the support and the layer in contact with the support can be improved.

(Barrier Layer)
In the preform of the present invention, the barrier layer contains a carboxyl group-containing resin and a polyvinyl alcohol-based resin.
Polyvinyl alcohol-based resins have a high cohesive force, and therefore have a high effect of blocking oxygen and water vapor (gas barrier properties), and also have excellent stretchability. Therefore, by including a polyvinyl alcohol-based resin in the barrier layer, a preform having excellent gas barrier properties can be obtained even after blow molding. In addition, the barrier layer can be prevented from breaking during blow molding, and the blow moldability of the preform can be improved.
The barrier layer contains a carboxyl group-containing resin, which allows the gas barrier properties to be maintained after blow molding, and such a barrier layer is easily soluble in acid or alkali, and can be easily separated and recovered by recovering, crushing and washing the bottle. Therefore, the preform having the barrier layer and the bottle obtained from this preform have excellent recyclability.
Furthermore, when the solvent of the coating solution used to form the barrier layer is water and/or a solvent having a hydroxyl group, the carboxyl group of the carboxyl-containing resin forms a hydrogen bond with these "-OH" groups, thereby improving the viscosity of the coating solution. This allows the thickness of the barrier layer to be ensured with fewer coating cycles, thereby improving the productivity of the preform.
Furthermore, in conventional bottles, in order to impart gas barrier properties to the bottle while it is in the bottle state, a process of reducing the pressure inside the bottle is required, and therefore the bottle wall thickness needs to be made greater than a certain value. However, the preform of the present invention can maintain gas barrier properties even after blow molding, so that the process of imparting gas barrier properties to the bottle state can be omitted, and as a result, the bottle wall thickness can be made thinner, enabling the preform and bottle to be made lighter.

In the barrier layer, the mass ratio of the carboxyl group-containing resin to the polyvinyl alcohol resin is preferably 1/20 or more and 10/1 or less, more preferably 1/15 or more and 5/1 or less, and even more preferably 1/10 or more and 2/1 or less.
By setting the mass ratio to 1/20 or more, the recyclability of the bottle can be further improved.
By setting the above mass ratio to 10/1 or less, the gas barrier properties after blow molding can be further improved.
The above mass ratio is a solid content ratio.

The carboxyl group-containing resin contained in the barrier layer of the preform can be an existing carboxyl group-containing resin. The existing carboxyl group-containing resin is a general term for resins that contain a carboxyl group in the polymer structure. Examples of the carboxyl group-containing resin include homopolymers of carboxyl group-containing unsaturated monomers, copolymers of carboxyl group-containing unsaturated monomers, copolymers of carboxyl group-containing unsaturated monomers and other polymerizable monomers, and polysaccharides containing a carboxyl group in the molecule (also called "acidic polysaccharides"). These carboxyl group-containing resins can be used alone or in combination of two or more.
The carboxy group includes not only a free carboxy group but also an acid anhydride group (specifically, a dicarboxylic acid anhydride group). The acid anhydride group may be partially ring-opened to form a carboxy group. In the carboxy group-containing resin, a part of the carboxy group may be neutralized with an alkali.

As the carboxy group-containing unsaturated monomer, α,β-monoethylenically unsaturated carboxylic acid is preferred. Therefore, the carboxy group-containing resin includes a homopolymer of α,β-monoethylenically unsaturated carboxylic acid, a copolymer of two or more kinds of α,β-monoethylenically unsaturated carboxylic acids, and a copolymer of α,β-monoethylenically unsaturated carboxylic acid and another polymerizable monomer. Examples of the other polymerizable monomer include an ethylenically unsaturated monomer.

Examples of the α,β-monoethylenically unsaturated carboxylic acid include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, etc., unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, etc., unsaturated dicarboxylic anhydrides such as maleic anhydride, itaconic anhydride, etc. These acids can be used alone or in combination of two or more kinds.
From the viewpoints of blow moldability and gas barrier properties after blow molding, the α,β-monoethylenically unsaturated carboxylic acid is preferably selected from one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and more preferably selected from one or more of acrylic acid, methacrylic acid, and maleic acid.

Examples of other polymerizable monomers, particularly ethylenically unsaturated monomers, copolymerizable with α,β-monoethylenically unsaturated carboxylic acids include ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; saturated carboxylic acid vinyl esters such as vinyl acetate; acrylic acid alkyl esters such as methyl acrylate and ethyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; chlorine-containing vinyl monomers such as vinyl chloride and vinylidene chloride; fluorine-containing vinyl monomers such as vinyl fluoride and vinylidene fluoride; unsaturated nitriles such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene and α-methylstyrene; itaconic acid alkyl esters; and the like. These monomers can be used alone or in combination of two or more.

Examples of carboxyl group-containing polysaccharides include acidic polysaccharides having a carboxyl group in the molecule, such as alginic acid, carboxymethylcellulose, and pectin. These acidic polysaccharides can be used alone or in combination of two or more. Acidic polysaccharides can also be used in combination with (co)polymers of α,β-monoethylenically unsaturated carboxylic acids.

When the carboxyl group-containing resin used in the present invention is a copolymer of α,β-monoethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers, from the viewpoints of recyclability, blow moldability, and gas barrier properties after blow molding, the composition of the copolymer is preferably such that the composition of α,β-monoethylenically unsaturated carboxylic acid monomer is 60 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

From the viewpoints of recyclability, blow moldability, and gas barrier properties after blow molding, the carboxyl group-containing resin is preferably a homopolymer or copolymer obtained by polymerization of only α,β-monoethylenically unsaturated carboxylic acid. When the polycarboxylic acid-based polymer is a (co)polymer consisting of only α,β-monoethylenically unsaturated carboxylic acid, the carboxyl group-containing resin is preferably a homopolymer, copolymer, or mixture of two or more thereof obtained from a carboxylic acid selected from one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, and more preferably a homopolymer, copolymer, or mixture of two or more thereof obtained from a carboxylic acid selected from one or more of acrylic acid, methacrylic acid, and maleic acid.

The carboxyl group-containing resin is preferably selected from one or more of polyacrylic acid, polymethacrylic acid, and maleic acid polymer. The carboxyl group-containing resin is more preferably polyacrylic acid, which is relatively easy to obtain and has good recyclability, blow moldability, barrier properties after blow molding, and preform productivity.

From the viewpoint of moldability of preforms and bottles, the number average molecular weight of the carboxyl group-containing resin is preferably in the range of 2,000 to 10,000,000, more preferably in the range of 5,000 to 1,000,000, and even more preferably in the range of 10,000 to 500,000. The number average molecular weight can be measured by gel permeation chromatography (GPC). In GPC measurements, the number average molecular weight of the polymer is generally measured in terms of standard polystyrene.

The content of the carboxy group-containing resin is preferably from 1 mass % to 80 mass %, more preferably from 2 mass % to 70 mass %, and even more preferably from 5 mass % to 60 mass %, based on all components contained in the barrier layer.
By setting the content of the carboxyl group-containing resin to 1% by mass or more, the recyclability of the bottle can be further improved.
By setting the content of the carboxyl group-containing resin to 80% by mass or less, the gas barrier property after blow molding can be further improved.

The polyvinyl alcohol resin (also called "PVA resin") contained in the barrier layer of the preform is a resin that contains an alcoholic hydroxyl group in the polymer structure. PVA resins are usually obtained by saponifying vinyl ester polymers.

Vinyl ester polymers are usually obtained by polymerizing vinyl ester monomers as polymerization components. Examples of vinyl ester monomers include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caprylate, vinyl versatate, and vinyl monochloroacetate, as well as aromatic carboxylic acid vinyl esters such as vinyl arene carboxylates (e.g., C7-12 arene carboxylic acid vinyl esters) such as vinyl benzoate. These monomers can be used alone or in combination of two or more.

The vinyl ester polymer may have units derived from other polymerizable monomers (monomers copolymerizable with vinyl esters). Examples of other polymerizable monomers include ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; chlorine-containing vinyl monomers such as vinyl chloride and vinylidene chloride; fluorine-containing vinyl monomers such as vinyl fluoride and vinylidene fluoride; unsaturated nitriles such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene and α-methylstyrene; itaconic acid alkyl esters; and the like. These monomers can be used alone or in combination of two or more.

The PVA-based resin may be one in which some of the vinyl alcohol units have been modified by reactions such as acetalization, etherification, acetoacetylation, and cationization.

The polymerization degree of the PVA-based resin is preferably 1,000 or more and 4,000 or less, more preferably 1,500 or more and 3,500 or less, and even more preferably 2,000 or more and 3,000 or less, from the viewpoint of moldability of the preform and the bottle.
The average degree of polymerization of the PVA-based resin can be measured in accordance with JIS K 6726:1994.

From the viewpoints of excellent solubility in a solvent and excellent storage stability of the composition, the saponification degree of the PVA-based resin is preferably from 70 mol % to 99.9 mol %, more preferably from 90 mol % to 99.5 mol %, and even more preferably from 95 mol % to 99.5 mol %.
The degree of saponification of the PVA-based resin can be measured in accordance with JIS K 6726:1994.

When the PVA-based resin is dissolved in pure water to give a concentration of 4 mass %, the aqueous solution viscosity is preferably 3 mPa·s or more and 70 mPa·s or less, more preferably 50 mPa·s or more and 68 mPa·s or less, and even more preferably 54 mPa·s or more and 66 mPa·s or less.
The viscosity of the coating liquid can be measured at a temperature of 20° C. in accordance with JIS Z 8803:2011.

PVA-based resins can be used alone or in combination of two or more types.

The content of the polyvinyl alcohol-based resin is preferably 20% by mass or more and 99% by mass or less, more preferably 30% by mass or more and 98% by mass or less, and even more preferably 40% by mass or more and 95% by mass or less, based on all components contained in the barrier layer.
By setting the content of the polyvinyl alcohol-based resin to 20% by mass or more, the gas barrier property after blow molding can be further improved.
By setting the content of the polyvinyl alcohol-based resin to 99% by mass or less, the recyclability of the bottle can be further improved.

The barrier layer of the preform may contain additives to the extent that the properties of the present invention are not impaired. Examples of additives include oxygen absorbers, plasticizers, UV stabilizers, antioxidants, coloring inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and colorants. These additives may be used alone or in combination of two or more.

The barrier layer of the preform may be a single layer or may be a multi-layer consisting of two or more layers. In addition, if the barrier layer is a multi-layer, each layer may have the same composition or different compositions.

The thickness of the barrier layer of the preform is preferably 2.0 μm or more and 1000.0 μm or less, and more preferably 20.0 μm or more and 500.0 μm or less, which can further improve the blow moldability and the gas barrier property after blow molding.
The thickness of the barrier layer of the preform can be measured, for example, at the body of the preform, and means the location where the thickness is the thinnest. In addition, when the barrier layer has multiple layers, the thickness of the barrier layer is the total thickness of all the layers.

(Protective Layer)
In the preform of the present invention, the protective layer is for protecting the barrier layer and contains a thermoplastic resin. The preform has the protective layer, which can prevent deterioration of the barrier function due to physical factors such as damage or peeling of the barrier layer or chemical factors such as moisture absorption or dissolution during the production and use of the preform and bottle.
Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, acrylic resin, polyacetal, polyester, polyurethane, polyvinyl acetal, etc. These thermoplastic resins can be used alone or in combination of two or more.
The protective layer of the preform preferably comprises polyvinyl acetal.

The polyvinyl acetal contained in the protective layer is particularly preferably polybutyl butyral. Polyvinyl butyral is a polymer having a structural unit having a vinyl butyral group in the molecule. In particular, a polymer having at least a structural unit having a vinyl butyral group and a structural unit having a hydroxyl group, as represented by the following chemical formula (I), is preferred.

(In chemical formula (I), "l" is the mol % of the constituent units having a vinyl butyral group, and is expressed as the mol % of the total of the constituent units derived from butyralized vinyl alcohol. "m" represents the mol % of the constituent units derived from vinyl alcohol, and "n" represents the mol % of the constituent units derived from vinyl acetate. Both l and m are numbers greater than 0, and n may be 0.)

Polyvinyl butyral is obtained by reacting polyvinyl alcohol (also called "PVA") with butyraldehyde to acetalize it. When acetalizing PVA, it is difficult to completely acetalize PVA, and hydroxyl groups remain partially irreversibly. Therefore, polyvinyl butyral resin contains hydroxyl groups.
In addition, PVA is usually produced by saponifying polyvinyl acetate, but since a small amount of acetyl group often remains during the saponification process in the production process of polyvinyl alcohol, polyvinyl butyral generally has some acetyl group or hydroxy group remaining irreversibly. Therefore, polyvinyl butyral usually contains acetyl group, and a polymer having a structural unit having a vinyl butyral group, a structural unit having an acetyl group, and a structural unit having a hydroxy group is preferably used.

From the viewpoint of moldability of the preform and the bottle, and durability of the protective layer, the polyvinyl butyral has a butyralization degree of preferably 50 mol % or more and 90 mol % or less, more preferably 60 mol % or more and 85 mol % or less, and more preferably 65 mol % or more and 75 mol % or less.
The butyralization degree herein means a molar fraction obtained by dividing the amount of ethylene groups to which butyral groups are bonded by the total amount of ethylene groups in the main chain, and corresponds to the mole % (l) of the constituent units having a vinyl butyral group in the formula (I) above.

From the viewpoint of moldability of the preform and bottle, and durability of the protective layer, the polyvinyl butyral preferably contains 10 mol % or more and 40 mol % or less of structural units having a hydroxyl group, i.e., structural units (m) derived from vinyl alcohol, more preferably 14.9 mol % or more and 34 mol % or less, and even more preferably 24.5 mol % or more and 31 mol % or less.

In polyvinyl butyral, the content of structural units having an acetyl group, i.e., structural units (n) derived from vinyl acetate, is preferably 10 mol % or less, more preferably 0.1 mol % or more and 6 mol % or less, and even more preferably 0.5 mol % or more and 4 mol % or less.

Polyvinyl butyral may further contain structural units obtained by reacting vinyl alcohol with an aldehyde other than butyraldehyde to form acetalized units, and the content of such structural units is preferably 10 mol % or less.
In the chemical formula (I), the sum of l, m, and n is preferably 100 mol %.

From the viewpoint of moldability of the preform and bottle, and durability of the protective layer, the number average molecular weight of the polyvinyl butyral is preferably 15,000 to 90,000, more preferably 20,000 to 70,000, and even more preferably 25,000 to 65,000.

When polyvinyl butyral is dissolved in 5% by mass aqueous ethanol to give a concentration of 10% by mass, the aqueous solution viscosity is preferably 3 mPa·s or more and 300 mPa·s or less, more preferably 10 mPa·s or more and 280 mPa·s or less, and even more preferably 20 mPa·s or more and 260 mPa·s or less.
The viscosity of the coating liquid can be measured using a falling ball viscometer at a temperature of 20° C. in accordance with JIS Z 8803:2011.

The glass transition temperature (Tg) of the polyvinyl butyral is preferably 50° C. or higher and 100° C. or lower, more preferably 60° C. or higher and 80° C. or lower, from the viewpoints of moldability of the preform and bottle, and durability of the protective layer.
The glass transition temperature (Tg) can be obtained by measuring the change in heat quantity by DSC (differential scanning calorimetry) (DSC method).

The protective layer of the preform may contain additives to the extent that the properties of the present invention are not impaired. Examples of additives include oxygen absorbers, plasticizers, UV stabilizers, antioxidants, coloring inhibitors, matting agents, deodorants, flame retardants, weather resistance agents, antistatic agents, thread friction reducers, slip agents, mold release agents, antioxidants, ion exchange agents, and colorants. These additives may be used alone or in combination of two or more.

The protective layer of the preform may be a single layer or a multi-layer consisting of two or more layers. Also, if the barrier layer is multi-layered, each layer may have the same composition or different compositions.

The thickness of the protective layer of the preform is preferably 0.5 μm or more and 1000.0 μm or less, and more preferably 0.7 μm or more and 500.0 μm or less, which can further improve the deterioration resistance of the barrier layer.
The thickness of the protective layer of the preform can be measured, for example, at the body of the preform, and means the location where the thickness is the thinnest. In addition, when the protective layer is multi-layered, the thickness of the protective layer is the total thickness of all layers.

<Preform manufacturing method>
In one embodiment, the preform 10 shown in FIG. 1 is first produced by injection molding the support-forming material using a conventionally known device to produce a support 17 having a mouth portion 11, a body portion 12, and a bottom portion 13.
Next, a coating liquid containing a carboxyl group-containing resin, a polyvinyl alcohol-based resin, and a solvent is prepared.
Next, the coating liquid is applied to the body 12 and bottom 13 of the support 17 to form a coating film.
Next, the coating film is dried to remove the solvent, thereby forming the barrier layer 18, and the preform 10 shown in FIG. 1 can be manufactured.

The solvent used in the coating liquid is not particularly limited as long as it can dissolve the carboxyl group-containing resin and the polyvinyl alcohol-based resin. Examples of the solvent include water; alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, and n-pentyl alcohol; and polar organic solvents such as dimethyl sulfoxide, N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents can be used alone or in combination of two or more.
As the solvent, it is preferable to use water, alcohols, or a mixture thereof, and it is more preferable to use a mixed solvent of water and isopropyl alcohol. This improves the viscosity of the coating liquid and makes it possible to reduce the number of coatings, thereby improving the productivity of the preform.

In the coating liquid, the total concentration of the solids of the carboxyl group-containing resin and the polyvinyl alcohol-based resin is preferably 2% by mass or more and 15% by mass or less, and more preferably 3% by mass or more and 10% by mass or less. This allows the formation of a barrier layer with a uniform thickness.

The viscosity of the coating liquid is preferably 150 mPa·s or more and 300 mPa·s or less, and more preferably 190 mPa·s or more and 270 mPa·s or less, which can further improve the productivity of the preform.
The viscosity of the coating liquid can be measured using a rotational viscometer at a temperature of 20° C. in accordance with JIS Z 8803:2011.

The coating liquid can be applied by a conventional method, such as applying the coating liquid with a brush, immersing the preform in the coating liquid, or spraying the coating liquid onto the surface of the preform.

The drying temperature for the coating liquid is not particularly limited as long as it is a temperature at which the solvent can be removed, but is preferably from 20°C to 80°C, and more preferably from 50°C to 70°C.

In the manufacturing method of the preform of the present invention, if a protective layer is further formed on the outside of the barrier layer, after the barrier layer is formed, the protective layer can be formed by coating the outside of the barrier layer with a material for forming the protective layer and drying it.

The material for forming the protective layer may be dissolved in a solvent and then applied. The solvent is not particularly limited as long as it can dissolve and emulsify/disperse the material for forming the protective layer. For example, water, acetone, ethyl methyl ketone, methyl isobutyl ketone, ethyl acetate, methanol, ethanol, isopropanol, etc. can be used.

The drying temperature when forming the protective layer is not particularly limited as long as it is a temperature at which the solvent can be removed, but is preferably 20°C or higher and 80°C or lower, and more preferably 40°C or higher and 70°C or lower.

The method for producing a preform of the present invention may include a step of printing images such as patterns and letters on the surface of the preform.
Printing can be performed by a known method. Examples of printing methods include inkjet printing, gravure printing, offset printing, flexographic printing, thermal transfer printing, silk screen printing, pad printing, hot stamping, and cold stamping. For example, when using the inkjet method, a UV-curable ink is applied to the preform, and then irradiated with UV light to harden the ink, thereby forming a print. Printing may also be performed using a thermal transfer sheet.

<Bottle>
The bottle of the present invention is produced by blow molding the preform of the present invention, which makes it possible to obtain a bottle having excellent recyclability and gas barrier properties.

In the bottle of the present invention, the volume increase rate of the bottle relative to the preform is preferably 2 or more and 45 or less, more preferably 5 or more and 40 or less, and even more preferably 8 or more and 35 or less.
By increasing the volume increase rate by at least two times, the preform before blow molding can be made smaller.
Furthermore, by setting the volume increase rate to 45 times or less, the gas barrier properties of the bottle after blow molding can be further improved.
The volume increase rate of the bottle relative to the preform means the volume increase rate "V2/V1" when the volume of the preform excluding the mouth portion is V1 and the volume of the bottle excluding the mouth portion after blow molding is V2.

Figure 3 is a schematic half-sectional view showing one embodiment of the bottle of the present invention. As shown in Figure 3, the bottle 20 has a mouth 21, a neck 22 provided below the mouth 21, a shoulder 23 provided below the neck 22, a body 24 provided below the shoulder 23, and a bottom 25 provided below the body 24.

The mouth portion 21 has a threaded portion 26 to which a cap (not shown) is screwed, a cap 27 provided below the threaded portion 26, and a support ring 28 provided below the cap 27. The shape of the mouth portion 21 may be a conventionally known shape.

The neck 22 is located between the support ring 28 and the shoulder 23, and has a generally cylindrical shape with a generally uniform diameter. The shoulder 23 is located between the neck 22 and the body 24, and has a shape whose diameter gradually increases from the neck 22 side toward the body 24 side.

The body 24 has a cylindrical shape with a generally uniform diameter overall. However, this is not limited thereto, and the body 24 may have a polygonal cylindrical shape such as a rectangular cylindrical shape or an octagonal cylindrical shape. Alternatively, the body 24 may have a cylindrical shape with a horizontal cross section that is not uniform from top to bottom. Furthermore, the body 24 has a generally flat surface without any irregularities, but this is not limited thereto. For example, the body 24 may have irregularities such as panels or grooves.

The bottom 25 has a recess 29 located in the center and a grounding portion 30 provided around the recess 29. The shape of the bottom 25 is not particularly limited, and may have any conventionally known bottom shape (e.g., a petaloid bottom shape, a rounded bottom shape, etc.).

As shown in Fig. 3, the bottle 20 includes a support 31 and a barrier layer 32. As shown in Fig. 3, the mouth 21 is formed of the support 31, and the neck 22, the shoulder 23, the body 24, and the bottom 25 are formed of the support 31 and the barrier layer 32. As shown in Fig. 3, the barrier layer 32 is provided on the outside of the bottle 20 so as to surround the bottle 20.
The barrier layer 32 may be provided over the entire or partial area of one or more selected from the neck portion 22, the shoulder portion 23, the body portion 24, and the bottom portion 25 (not shown).
The barrier layer 32 may be provided on the inside of the bottle 20 or may be provided between the support 31 and other layers (not shown).

In one embodiment, the bottle has a barrier layer provided over at least the entire outer area of the body. This allows the gas barrier properties of the bottle to be efficiently improved. It is preferable that the bottle has a barrier layer provided over at least the entire outer area of the shoulder and body.

In one embodiment, as shown in FIG. 4, when the bottom end of the mouth portion 21 is "0L" and the ground portion 30 is "1L", the bottle has a barrier layer 32 over the entire outer area of at least 0.4L to 0.6L. This makes it possible to efficiently improve the gas barrier properties of the bottle. It is preferable that the bottle has a barrier layer over the entire outer area of at least 0.1L to 0.8L, and it is more preferable that the barrier layer be provided over the entire outer area of at least 0.05L to 0.95L.

The bottle 20 of the present invention may be provided with a protective layer (not shown) on the inside and/or outside of the barrier layer 32 .
The bottle 20 of the present invention may also have a vapor deposition film (not shown).

In the bottle of the present invention, the oxygen transmission rate is preferably 0.100 cc/day bottle 0.21 atm or less, more preferably 0.075 cc/day bottle 0.21 atm or less, even more preferably 0.050 cc/day bottle 0.21 atm or less, and even more preferably 0.040 cc/day bottle 0.21 atm or less.
In the present invention, the oxygen permeability is a value measured in accordance with JIS K 7126-2:2006 using an oxygen permeability measuring device (for example, OX-TRAN 2/20, product name, manufactured by MOCON Corporation) under conditions of 23° C. and humidity of 40% RH, and is a value obtained by measuring the entire bottle with the mouth portion sealed with a jig and dividing the measured value by the surface area of the entire bottle excluding the mouth portion.

The cross-sectional thickness of the bottle is preferably 0.1 mm or more and 0.4 mm or less, and more preferably 0.15 mm or more and 0.3 mm or less.
The cross-sectional thickness of the bottle can be measured, for example, at the body of the bottle having at least the support and the barrier layer, and means the point where the cross-sectional thickness is the thinnest.

The volume/weight of the bottle of the present invention is preferably 5 mL/g or more and 50 mL/g or less, and more preferably 8 mL/g or more and 45 mL/g or less.
By setting the volume/weight of the bottle to 5 mL/g or more, the weight of the bottle can be reduced.
Furthermore, by setting the volume/weight of the bottle to 50 mL/g or less, the strength of the bottle can be improved.

The bottle of the present invention may have a full capacity of, for example, 100 mL or more and 2000 mL or less. The full capacity of the bottle is preferably 280 mL or more and 750 mL or less.
The bottle of the present invention may be a large bottle having a full capacity of, for example, 10 L or more and 60 L or less.

The bottle of the present invention may be printed. The image formed by printing is not particularly limited, and examples thereof include patterns and letters. From the viewpoint of not being affected by the color tone of the bottle, it is preferable that the printing is performed on the outer surface of the bottle.
Printing can be carried out by a known method, such as an inkjet method, a gravure printing method, an offset printing method, a flexographic printing method, a thermal transfer method, a silk screen method, a pad method, a hot stamp method, or a cold stamp method.
Furthermore, a printed bottle can be obtained by blow molding a printed preform.

The bottle's support, barrier layer, protective layer and vapor deposition film are explained below.

(Support)
The material for the support of the bottle can be the same as the material for the support in the preform of the present invention.

The bottle support may have a single layer structure or a multi-layer structure of two or more layers. In addition, if the support has a multi-layer structure, each layer may have the same composition or different compositions.

The cross-sectional thickness of the bottle support is preferably 0.01 mm or more and 0.35 mm or less, and more preferably 0.05 mm or more and 0.25 mm or less.
The cross-sectional thickness of the bottle support can be measured at the body of the bottle, and refers to the point where the cross-sectional thickness is the thinnest.

(Barrier Layer)
The material for the barrier layer of the bottle can be the same as the material for the barrier layer in the preform of the present invention.

The barrier layer of the bottle may be a single layer or may be a multi-layer consisting of two or more layers. Furthermore, if the barrier layer is a multi-layer, each layer may have the same composition or different compositions.

The thickness of the barrier layer of the bottle is preferably 0.1 μm or more and 200.0 μm or less, and more preferably 5.0 μm or more and 50.0 μm or less, which can further improve the gas barrier property of the bottle.
The thickness of the barrier layer of the bottle can be measured, for example, at the body of the bottle, and means the part where the thickness is the thinnest. In addition, when the barrier layer has multiple layers, the thickness of the barrier layer is the sum of the thicknesses of all the layers.

(Protective Layer)
The material for the protective layer of the bottle can be the same as the material for the protective layer in the preform of the present invention.

The protective layer of the bottle may be a single layer or may be multiple layers of two or more layers. Furthermore, if the protective layer is multiple layers, each layer may have the same composition or different compositions.

The thickness of the protective layer of the bottle is preferably 0.1 μm or more and 200.0 μm or less, and more preferably 0.7 μm or more and 70.0 μm or less, which can further improve the deterioration resistance of the barrier layer.
The thickness of the protective layer of the bottle can be measured, for example, at the body of the bottle, and means the thinnest point. In addition, when the protective layer has multiple layers, the thickness of the protective layer is the total thickness of all layers.

(Deposition layer)
The bottle of the present invention may have a vapor-deposited film in order to further improve the gas barrier properties.

Examples of the vapor-deposited film include vapor-deposited films composed of metals such as aluminum, inorganic oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide, organosilicon compounds such as hexamethyldisiloxane, and hard carbon films such as DLC (Diamond Like Carbon) films.
The hard carbon film made of DLC film is a hard carbon film also called an i-carbon film or a hydrogenated amorphous carbon film (aC:H), which is an amorphous carbon film mainly composed of SP3 bonds.

The thickness of the deposited film is not particularly limited, and can be, for example, 1 nm or more and 150 nm or less.
The thickness of the vapor-deposited layer can be measured, for example, at the body of the bottle, and refers to the location where the thickness is the thinnest.

The deposition film can be formed by a conventional method, for example, physical vapor deposition methods (PVD method) such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition methods (CVD method) such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

<Bottle manufacturing method>
In one embodiment, the bottle 20 shown in Fig. 3 can be produced by blow molding the preform 10 shown in Fig. 1. The blow molding can be carried out by a conventionally known method.

[Example 1]
Pellets of polyethylene terephthalate (PET) were prepared.
The PET was melted and injected into an injection molding machine to produce a support having a mouth, a body, and a bottom. The mouth of the support has a screw portion, a cap, and a support ring in this order from above the mouth.

Separately, 1.88 g of polyacrylic acid (manufactured by Nippon Shokubai Co., Ltd., trade name: AS-58, number average molecular weight: 106,000) was dissolved in 43.5 g of water. Separately, 18.82 g of PVA (manufactured by Kuraray Co., Ltd., trade name: PVA-124, polymerization degree: 2400, saponification degree: 98-99%) was dissolved in a mixed solvent of 414.0 g of water and 21.8 g of isopropyl alcohol (IPA). These solutions were mixed to prepare a coating liquid (viscosity: 263.4 mPa·s (20°C)). This coating liquid was applied to the trunk and bottom of the support to form a coating film, and the coating film was dried at 50°C for 10 minutes. The formation and drying of this coating film was performed a total of five times to obtain a preform having a barrier layer. The mass ratio (solid content ratio) of polyacrylic acid to PVA was 1/10.
The cross-sectional thickness of the body of the preform was 2.0 mm, and the thickness of the barrier layer was 100.0 μm.

The preform was then heated to 110°C and biaxially stretched and blow molded in a blow molding die to obtain a bottle with a capacity of 500 mL and including a mouth, neck, shoulder, body, and bottom. A barrier layer was formed on the outer surfaces of the neck, shoulder, body, and bottom of the bottle. The cross-sectional thickness of the bottle body was 0.15 mm, and the thickness of the barrier layer was 20.0 μm.

[Example 2]
A preform was obtained in the same manner as in Example 1, except that a solution in which 3.45 g of polyacrylic acid was dissolved in 79.9 g of water and a solution in which 17.25 g of PVA was dissolved in a mixed solvent of 379.4 g of water and 20.0 g of IPA were mixed to prepare a coating liquid (viscosity: 256.4 mPa·s (20°C)). The mass ratio of polyacrylic acid to PVA was 1/5. The cross-sectional thickness of the trunk of the preform was 2.0 mm, and the thickness of the barrier layer was 100.0 μm.

Next, in the same manner as in Example 1, a bottle was obtained from the preform of this example.
The cross-sectional thickness of the bottle body was 0.15 mm, and the thickness of the barrier layer was 20.0 μm.

[Example 3]
A preform was obtained in the same manner as in Example 1, except that a solution in which 6.90 g of polyacrylic acid was dissolved in 159.8 g of water and a solution in which 13.80 g of PVA was dissolved in a mixed solvent of 303.5 g of water and 16.0 g of IPA were mixed to prepare a coating liquid (viscosity: 230.1 mPa·s (20°C)). The mass ratio of polyacrylic acid to PVA was 1/2. The cross-sectional thickness of the trunk of the preform was 2.0 mm, and the thickness of the barrier layer was 100.0 μm.

Next, in the same manner as in Example 1, a bottle was obtained from the preform of this example.
The cross-sectional thickness of the bottle body was 0.15 mm, and the thickness of the barrier layer was 20.0 μm.

[Example 4]
A preform was obtained in the same manner as in Example 1, except that a solution of 10.35 g of polyacrylic acid dissolved in 239.7 g of water and a solution of 10.35 g of PVA dissolved in a mixed solvent of 227.7 g of water and 12.0 g of IPA were mixed to prepare a coating liquid (viscosity: 195.5 mPa·s (20°C)). The mass ratio of polyacrylic acid to PVA was 1/1. The cross-sectional thickness of the trunk of the preform was 2.0 mm, and the thickness of the barrier layer was 100.0 μm.

Next, in the same manner as in Example 1, a bottle was obtained from the preform of this example.
The cross-sectional thickness of the bottle body was 0.15 mm, and the thickness of the barrier layer was 20.0 μm.

[Comparative Example 1]
A preform was obtained in the same manner as in Example 1, except that no barrier layer was formed on the support.

Next, in the same manner as in Example 1, a bottle was obtained from the preform of this comparative example.
The cross-sectional thickness of the bottle body was 0.12 mm.

[Comparative Example 2]
A preform was obtained in the same manner as in Example 1, except that a coating liquid (viscosity: 115 mPa·s (20° C.)) was prepared by dissolving only 21.5 g of polyacrylic acid in 240.5 g of water, and a coating film was formed and dried using this coating liquid a total of 15 times to form a barrier layer. The cross-sectional thickness of the trunk part of the preform was 2.0 mm, and the thickness of the barrier layer was 100.0 μm.

Next, in the same manner as in Example 1, a bottle was obtained from the preform of this comparative example.
The cross-sectional thickness of the bottle body was 0.15 mm, and the thickness of the barrier layer was 20.0 μm.

<<Recyclability evaluation>>
The bottles obtained in the above Examples and Comparative Examples were crushed into flakes, which were then immersed in water at 50° C. for 15 minutes to evaluate the solubility of the barrier layer according to the following criteria. The evaluation results are shown in Table 1. The recyclability evaluation was performed by mixing a small amount of red colorant into the above coating liquid to color the barrier layer.
(Evaluation Criteria)
A: The barrier layer on the surface of the flake was completely removed, and the flake became colorless and transparent.
B: The barrier layer remained on the surface of the flake, and the flake was colored red.

<<Blow moldability evaluation>>
The appearance of the bottles obtained in the above Examples and Comparative Examples was visually observed, and the blow moldability of the barrier layer was evaluated according to the following criteria. The evaluation results are shown in Table 1.
(Evaluation Criteria)
A: The barrier layer was not broken.
B: Part of the barrier layer was broken, but the breakage was not significant enough to be considered a product.
C: The barrier layer was completely broken, and the level was problematic for the product.

<<Gas barrier property evaluation>>
The oxygen transmission rate of the bottles obtained in the above Examples and Comparative Examples was measured to evaluate the gas barrier properties of the bottles. The oxygen transmission rate was measured in accordance with JIS K 7126-2:2006 using an oxygen gas transmission rate measuring device (manufactured by MOCON, product name: OX-TRAN2/20) under conditions of 23°C and 40% RH. The oxygen transmission rate was measured for the entire bottle with the mouth closed with a jig, and the value was divided by the surface area of the entire bottle excluding the mouth. The measurement results are shown in Table 1. The bottle of Comparative Example 2 was not evaluated for gas barrier properties because the barrier layer was completely broken.

Reference Signs List 10: Preform 11: Mouth 12: Body 13: Bottom 14: Threaded part 15: Turnip 16: Support ring 17: Support body 18: Barrier layer 20: Bottle 21: Mouth 22: Neck 23: Shoulder 24: Body 25: Bottom 26: Threaded part 27: Turnip 28: Support ring 29: Recess 30: Ground part 31: Support body 32: Barrier layer

Claims (7)

A bottle obtained by blow molding a preform including a support, a barrier layer, and a protective layer provided on a surface of the barrier layer,
the support comprises polyester;
the barrier layer is made of a dry coating film containing a polyvinyl alcohol-based resin and a carboxyl group-containing resin ,
the barrier layer contains the polyvinyl alcohol-based resin in a proportion of 40% by mass or more and 95% by mass or less with respect to all components contained in the barrier layer. The bottle has a mouth, a neck provided below the mouth, a shoulder provided below the neck, a body provided below the shoulder, and a bottom provided below the body,
The lower end of the mouth is 0L,
The bottom is 1 L,
When
The bottle according to claim 1, wherein the barrier layer is provided over an entire area of at least 0.4 L to 0.6 L. The bottle according to claim 1, having an oxygen permeability of 0.100 cc/day/bottle/0.21 atm or less. The bottle according to claim 1, wherein the cross-sectional thickness of the bottle is 0.1 mm or more and 0.4 mm or less. The bottle according to claim 1, having a volume/weight of 5 mL/g or more and 50 mL/g or less. The bottle according to claim 1, wherein the thickness of the barrier layer in the body of the bottle is 0.1 μm or more and 200.0 μm or less. The bottle according to claim 1, wherein the thickness of the protective layer on the body of the bottle is 0.1 μm or more and 200.0 μm or less.