Shoe-shaped press belt and method for preparing the same

Abstract

The present invention provides a shoe press belt having excellent strength while suppressing uneven strength between parts and a method for producing the shoe press belt. A shoe press belt for a papermaking machine, comprising at least one resin layer containing a polyurethane resin, wherein the polyurethane resin contains a polyurethane resin having the following formula (1) (wherein R 1 A polycarbonate diol having one or more units A represented by a branched alkylene group having 3 or more and 20 or less carbon atoms is used as a component.

Description

Technical Field

[0001] The invention relates to a shoe-shaped press belt and a method for preparing the shoe-shaped press belt. Background Art

[0002] A papermaking machine for removing moisture from paper raw materials generally includes a wire section, a press section, and a dryer section, which are arranged in this order along the conveying direction of the wet paper.

[0003] The wet paper is sequentially transferred to each papermaking tool provided in the wire section, the press section, and the drying section, and the water is removed while being conveyed, and finally dried in the drying section. In each of these sections, papermaking tools corresponding to each function such as dehydrating the wet paper (wire section), squeezing water (press section), and drying (drying section) are used.

[0004] The pressing section usually includes one or more pressing devices arranged in series along the conveying direction of the wet paper. An endless felt is arranged in each pressing device, or an endless felt is formed by connecting an end of a felt to a papermaking machine. Moreover, each pressing device has a rolling mechanism composed of a pair of rollers facing each other, or a shoe-shaped pressing mechanism having an annular shoe-shaped pressing belt sandwiched between concave shoes facing the rollers. The felt on which the wet paper is placed is moved along the conveying direction of the wet paper and is pressurized by passing through the rolling mechanism or the shoe-shaped pressing mechanism, so that the felt continuously absorbs its moisture or the moisture passes through the inside of the felt and is discharged to the outside, thereby squeezing moisture from the wet paper.

[0005] In a shoe press belt, a reinforcing matrix is ​​usually embedded in a resin, and the resin constitutes an outer peripheral layer in contact with the felt and an inner peripheral layer in contact with the shoe. In addition, since the shoe press belt reciprocates between the pressurized roll and the shoe, the resin of the shoe press belt is required to have excellent durability.

[0006] Patent document 1 provides a shoe press belt, in which a reinforcing substrate is buried in polyurethane for the purpose of preventing the welding area constituting the drainage groove from being broken or damaged and suppressing the occurrence of cracks in the shoe press belt having a drainage groove. The polyurethane and the reinforcing substrate are integrated to form a shoe press belt, and the polyurethane constituting at least the outer peripheral surface of the shoe press belt is a thermosetting polyurethane obtained by curing a urethane prepolymer using a curing agent. The urethane prepolymer includes a first urethane prepolymer, and the first urethane prepolymer is obtained by reacting a polyol component containing a specified straight-chain aliphatic polycarbonate diol with an aromatic diisocyanate.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2016-199813 Summary of the invention

[0010] Technical issues

[0011] The strength of the shoe press belt provided with a polyurethane layer having a linear aliphatic polycarbonate diol as a component of the urethane prepolymer is excellent. On the other hand, the present inventors have found that when a linear aliphatic polycarbonate diol is used as a component of the urethane prepolymer, strength imbalance occurs between the components of the obtained shoe press belt. If there is strength imbalance between the components of the shoe press belt, the shoe press belt is damaged and deteriorated starting from the portion with low strength, and as a result, it becomes difficult to improve the durability of the shoe press belt.

[0012] Therefore, an object of the present invention is to provide a shoe press belt having excellent strength while suppressing unevenness in strength between components, and a method for producing the shoe press belt.

[0013] Solutions to the problem

[0014] As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that the strength of the polyurethane layer constituting the shoe press belt can be improved and strength unevenness can be suppressed by adding a specific polycarbonate diol to the shoe press belt, thereby completing the present invention.

[0015] The gist of the present invention is as follows.

[0016] [1] A shoe press belt for a papermaking machine,

[0017] having at least one resin layer comprising a polyurethane resin,

[0018] The above-mentioned polyurethane resin contains, as a component, a polycarbonate diol containing one or more units A represented by the following formula (1).

[0019] Chemical formula 1:

[0020]

[0021] In formula (1),

[0022] R 1 It is a branched alkylene group having 3 or more and 20 or less carbon atoms.

[0023] [2] The shoe press belt according to [1], R 1 It is selected from the group consisting of 3-methylpentenyl, 2,2-dimethylpropenyl, 2-methyloctenyl, 2-butyl-2-ethylpropenyl and 2,2,4-trimethyl-1,6-hexenyl.

[0024] [3] The shoe press belt according to [1], wherein the polycarbonate diol further comprises one or more units B represented by the following formula (2):

[0025] Chemical formula 2:

[0026]

[0027] In formula (2),

[0028] R 2 It is a straight-chain alkylene group having 1 to 20 carbon atoms.

[0029] [4] The shoe press belt according to [3], R 2 is selected from the group consisting of n-butenyl, n-hexenyl, n-nonenyl, n-decenyl, n-undecenyl and n-dodecenyl.

[0030] [5] The shoe press belt according to any one of [1] to [4], wherein the polyurethane resin is obtained by reacting a urethane prepolymer having an isocyanate group containing one or more of the polycarbonate diols as a component with a curing agent having an active hydrogen group.

[0031] [6] According to the shoe press belt described in [5], the above-mentioned urethane prepolymer is obtained by reacting a polyisocyanate compound with a polyol compound, the above-mentioned polyisocyanate compound contains one or more selected from p-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, and the above-mentioned polyol compound contains one or more of the above-mentioned polycarbonate diols.

[0032] [7] The shoe press belt according to [6], wherein the polyol compound further comprises polytetramethylene ether glycol and / or polyhexamethylene carbonate glycol.

[0033] [8] The shoe press belt according to any one of [5] to [7], wherein the curing agent contains one or more of the polycarbonate diols.

[0034] [9] The shoe press belt according to any one of [1] to [4], wherein the polyurethane resin is obtained by reacting a urethane prepolymer having an isocyanate group with a curing agent having an active hydrogen group containing one or more of the polycarbonate diols.

[0035]

[10] The shoe press belt according to [9], wherein the curing agent further comprises an alkylene glycol compound, dimethylthiotoluenediamine and / or diethyltoluenediamine.

[0036]

[11] The shoe press belt according to [9] or

[10] , wherein the curing agent comprises 1,4-butanediol, dimethylthiotoluenediamine and / or diethyltoluenediamine.

[0037]

[12] The shoe press belt according to any one of [9] to

[11] , wherein the urethane prepolymer is obtained by reacting a polyisocyanate compound with a polyol compound containing a polyether polyol and / or a linear aliphatic polycarbonate diol.

[0038]

[13] The shoe press belt according to any one of [1] to

[12] , wherein the resin layer comprises a first layer constituting an outer peripheral surface of the shoe press belt,

[0039] The first layer includes the polyurethane resin.

[0040]

[14] The shoe press belt according to any one of [1] to

[13] , wherein the resin layer has a second layer constituting an inner peripheral surface of the shoe press belt,

[0041] The second layer includes the polyurethane resin.

[0042]

[15] A method for producing a shoe press belt for a papermaking machine, comprising the steps of forming a resin layer containing a polyurethane resin by curing a polyurethane raw material,

[0043] The polyurethane raw material comprises, as a constituent unit, a polycarbonate diol containing one or more units A represented by the following formula (1):

[0044] Chemical formula 3:

[0045]

[0046] In formula (1),

[0047] R 1 It is a branched alkylene group having 3 or more and 20 or less carbon atoms.

[0048] Effects of the Invention

[0049] With the above structure, it is possible to provide a shoe press belt having excellent strength while suppressing uneven strength between components, and a method for producing the shoe press belt. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A cross-sectional view of a machine showing a shoe press belt according to an embodiment of the present invention.

[0051] Figure 2 A cross-sectional view of a machine showing a shoe press belt according to another embodiment of the present invention.

[0052] Figure 3 It is a schematic diagram for explaining a preferred embodiment of the method for producing a shoe press belt according to the present invention.

[0053] Figure 4 It is a schematic diagram for explaining a preferred embodiment of the method for producing a shoe press belt according to the present invention.

[0054] Figure 5 It is a schematic diagram for explaining a preferred embodiment of the method for producing a shoe press belt according to the present invention.

[0055] Description of Reference Numerals

[0056] 1.1A: Shoe-shaped press belt

[0057] 10: Reinforced fiber substrate layer

[0058] 11: Reinforced fiber substrate

[0059] 13: Resin

[0060] 20, 20A: First resin layer

[0061] 21: Peripheral surface

[0062] 23: Resin

[0063] 25: Drainage ditch

[0064] 30: Second resin layer

[0065] 31: Inner peripheral surface

[0066] 33: Resin DETAILED DESCRIPTION

[0067] Hereinafter, preferred embodiments of a shoe press belt and a method for manufacturing a shoe press belt according to the present invention will be described in detail with reference to the accompanying drawings.

[0068] 1. Shoe-shaped press belt

[0069] First, a shoe press belt according to a preferred embodiment of the present invention will be described.

[0070] Figure 1 The cross-machine direction is a cross-sectional view of an example of a shoe press belt according to a preferred embodiment of the present invention. In addition, in the figure, the size of each component is appropriately emphasized for the convenience of explanation, and the actual proportion and size of each component are not shown. The cross machine direction (Cross Machine Direction) is also referred to as "CMD", and the machine direction (Machine Direction) is also referred to as "MD".

[0071] Figure 1The shoe press belt 1 shown is used in the press section of a paper machine, more specifically, in a shoe press mechanism, to convey wet paper in cooperation with a felt and to squeeze water from the wet paper. The shoe press belt 1 forms an endless belt-like body. That is, the shoe press belt 1 is an endless belt. Moreover, the shoe press belt 1 is generally configured so that its circumferential direction is along the machine direction (MD) of the paper machine.

[0072] Figure 1 The shoe press belt 1 shown includes a reinforcing fiber base layer 10, a first resin layer 20 provided on one main surface located on the outer surface side of the reinforcing fiber base layer 10, and a second resin layer 30 provided on the other main surface located on the inner surface side of the reinforcing fiber base layer 10, and is formed by stacking these layers.

[0073] The reinforcing fiber substrate layer 10 is composed of a reinforcing fiber substrate 11 and a resin 13. The resin 13 is present in the reinforcing fiber substrate layer 10 to fill the spaces between the fibers in the reinforcing fiber substrate 11. That is, a part of the resin 13 is impregnated in the reinforcing fiber substrate 11, and on the other hand, the reinforcing fiber substrate 11 is buried in the resin 13.

[0074] The reinforcing fiber substrate 11 is not particularly limited, and for example, a fabric in which warp and weft are woven by a loom or the like is generally used. In addition, a lattice-like material obtained by overlapping warp rows and weft rows without weaving may also be used. Alternatively, two or more fabrics and lattice-like materials may be used in combination.

[0075] The fineness of the fibers constituting the reinforcing fiber substrate 11 is not particularly limited, and may be, for example, 300 to 10,000 dtex, and preferably 500 to 6,000 dtex.

[0076] Furthermore, the fineness of the fibers constituting the reinforcing fiber substrate 11 may be different depending on the location where the fibers are used. For example, the warp and weft of the reinforcing fiber substrate 11 may have different finenesses.

[0077] As the material of the reinforcing fiber substrate 11, polyester (polyethylene terephthalate and polybutylene terephthalate, etc.), aliphatic polyamide (polyamide 6, polyamide 11, polyamide 12 and polyamide 612, etc.), aromatic polyamide (aromatic polyamide), polyvinylidene fluoride, polypropylene, polyetheretherketone, polytetrafluoroethylene, polyethylene, wool, cotton and metal can be used alone or in combination of two or more.

[0078] And, the resin 13 will be described below.

[0079] The first resin layer 20 is a resin layer provided on one main surface located on the outer surface side of the reinforcing fiber base material layer 10, and is composed of a resin 23. The first resin layer 20 constitutes an outer peripheral surface 21 on which the wet paper is carried and conveyed via the felt when the shoe press belt 1 is used.

[0080] The second resin layer 30 is a resin layer provided on the other main surface located on the inner surface side of the reinforcing fiber base material layer 10, and is composed of a resin 33. The second resin layer 30 constitutes an inner peripheral surface 31, and when the shoe press belt 1 is used, the inner peripheral surface 31 is configured to contact the shoe of the shoe press mechanism (not shown).

[0081] Among them, the resin 13 in the reinforcing fiber base material layer 10 of the shoe press belt 1, the resin 23 constituting the first resin layer 20, and the resin 33 constituting the second resin layer 30 will be described.

[0082] In the present embodiment, at least one of the reinforcing fiber base material layer 10, the first resin layer 20 and the second resin layer 30 of the shoe press belt 1 contains a polyurethane resin. The polyurethane resin contains a polycarbonate diol X containing one or more units A represented by the following formula (1) as a component:

[0083] Chemical formula 4:

[0084]

[0085] In formula (1),

[0086] R 1 It is a branched alkylene group having 3 or more and 20 or less carbon atoms.

[0087] Since the resin 13, the resin 23 and the resin 33 may have the same structure, the resin 23 of the first resin layer 20 will be described in detail below as a representative example. In addition, in the following description, the case where the resin 23 includes a polyurethane resin containing the above-mentioned polycarbonate diol X as a component will be focused on.

[0088] The polyurethane resin constituting the resin 23 contains the above-mentioned polycarbonate diol X as a component. Thus, the strength of the first resin layer 20 composed of the resin 23 is improved while suppressing uneven strength in the first resin layer 20, and as a result, the strength of the shoe press belt 1 is improved while suppressing uneven strength between components.

[0089] As described in detail below, the polyurethane layer containing a linear aliphatic polycarbonate diol as a component of the urethane prepolymer is excellent in strength. On the other hand, the present inventors have found that when a linear aliphatic polycarbonate diol is used as a component of the urethane prepolymer, strength imbalance occurs between the components of the obtained shoe press belt. If there is strength imbalance between the components of the shoe press belt, the shoe press belt is damaged and deteriorated starting from the portion with low strength, and as a result, it becomes difficult to improve the durability of the shoe press belt.

[0090] As a result of intensive research to clarify the cause, the present inventors found that when a urethane prepolymer is prepared using a linear aliphatic polycarbonate diol, the viscosity of the polyurethane composition obtained by mixing the urethane prepolymer and the curing agent with the urethane prepolymer greatly increases, and when a shoe press belt is prepared, the polyurethane composition cannot be uniformly discharged and applied. In this case, it is difficult to form a uniform polyurethane layer.

[0091] On the other hand, the present inventors have found that when a polycarbonate diol X containing a unit A represented by the above formula (1) is used, the viscosity increase of the obtained polyurethane composition can be suppressed, and a uniform polyurethane resin layer can be formed. In addition, when a resin layer is formed by using the above polycarbonate diol X in this way, not only is the strength unevenness between the parts of the shoe press belt suppressed, but the overall strength of the shoe press belt is also improved.

[0092] Furthermore, in this specification, unless otherwise specified, "between components" refers to the resin layer constituting the shoe press belt, that is, between arbitrary components in the plane direction of the resin layer formed of the same material. For example, in the shoe press belt 1 according to the present embodiment, between arbitrary components in the plane direction of each resin layer can be compared in each of the reinforcing fiber base material layer 10, the first resin layer 20, and the second resin layer 30. Furthermore, the strength imbalance between components in each resin layer has a complex influence on the shoe press belt, and the strength imbalance between components constituting the shoe press belt itself.

[0093] It is known that a polyurethane resin using a linear aliphatic polycarbonate diol generally has a high crystallinity and excellent strength compared to a case where an aliphatic polycarbonate diol derived from a branched alkylene glycol is used. However, in the present embodiment, contrary to this common sense, by using a polycarbonate diol X containing a unit A represented by the above formula (1), it was found that a shoe press belt 1 having a comparable strength can be obtained even when compared to a case where a linear aliphatic polycarbonate is used.

[0094] In particular, the first resin layer 20 constitutes the outer peripheral surface 21 of the shoe press belt 1. In the shoe press belt 1, the outer peripheral surface 21 is a portion where damage such as cracks is easily generated due to wear of the shoe press belt 1 caused by contact and friction with felt or the like when the shoe press belt 1 is used and due to bending fatigue of the shoe press belt 1. Therefore, the first resin layer 20 constituting the outer peripheral surface 21 of the shoe press belt 1 includes a polyurethane resin formed using polycarbonate diol X, thereby improving the durability of the shoe press belt 1.

[0095] In the above formula (1), R 1 is a branched alkylene group having 3 or more and 20 or less carbon atoms, and each occurrence is the same or different. Specifically, R 1 The alkylene group may be an alkylene group having 3 or more and 20 or less carbon atoms represented by the following formula (3).

[0096] Chemical formula 5:

[0097]

[0098] In formula (3), R 3 is a straight chain or branched chain alkyl group,

[0099] R 4 is H or a straight-chain or branched-chain alkyl group,

[0100] R 5 is a straight chain or branched chain alkylene group,

[0101] A is an integer greater than or equal to 0.

[0102] In R 3 and R 4 In the example, the straight-chain alkyl group may be methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl. 3 and R 4 In the above, the branched alkyl group may include isopropyl, tert-butyl and isobutyl.

[0103] Preferably, R 3 It is a straight-chain or branched alkyl group having 1 to 4 carbon atoms, more preferably, one selected from methyl, ethyl, n-propyl, n-butyl and isopropyl, more preferably, methyl, ethyl or n-butyl.

[0104] Preferably, R 4 It is H or a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably, one selected from the group consisting of H, methyl, ethyl, n-propyl and isopropyl, more preferably, H, methyl or ethyl.

[0105] As R 5Examples of the straight-chain alkylene group include straight-chain alkylene groups having 1 to 10 carbon atoms, such as methylene, vinyl, n-propenyl, n-butenyl, n-pentenyl, n-hexenyl, n-heptenyl, and n-octenyl. 5 The branched alkylene group may include, for example, 1-methylpropenyl, 2-methylpropenyl, 1,1-dimethylpropenyl, 1,2-dimethylpropenyl, 1,3-dimethylpropenyl, 2,2-dimethylpropenyl, 1,2,3-trimethylpropenyl, 1,1,2-trimethylpropenyl, 1,2,2-trimethylpropenyl, 1,1,3-trimethylpropenyl, 1-methylbutenyl, 2-methylbutenyl, 1,1-dimethylbutenyl, 1,2-dimethylbutenyl, 1,3-dimethylbutenyl, 1,4-dimethylbutenyl, 2,2-dimethylbutenyl, 2,3-dimethylbutenyl, 1,2,3-trimethylbutenyl, 1,2,4-trimethylbutenyl, 1,1,2-trimethylbutenyl, 1,2,2-trimethylbutenyl, 1,3,3-trimethylbutenyl, 1-methylpentenyl, 2-methylpentenyl, 3-methylpentenyl, 1-methylhexenyl, 2-methylhexenyl and 3-methylhexenyl, etc.

[0106] Preferably, R 5 It is a straight-chain alkylene group having 1 to 10 carbon atoms, more preferably a straight-chain alkylene group having 1 to 8 carbon atoms, and more preferably one selected from the group consisting of methylene, vinyl and n-hexenyl.

[0107] In the above formula (3), a is an integer greater than or equal to 0. Preferably, a is greater than or equal to 1. The upper limit of a is 17 or less, so that the number of carbon atoms in formula (3) becomes 20. Preferably, a is 6 or less, and more preferably, 3 or less.

[0108] Particularly preferably, R 1 The present invention is selected from 3-methylpentenyl, 2,2-dimethylpropenyl, 2-methyloctenyl, 2-butyl-2-ethylpropenyl and 2,2,4-trimethyl-1,6-hexenyl. As a result, the viscosity of the obtained polyurethane composition can be further suppressed, and the imbalance between the parts of the shoe press belt 1 can be further suppressed, and the strength of the shoe press belt 1 can be further improved.

[0109] Furthermore, the polycarbonate diol X may contain one or more units B represented by the following formula (2):

[0110] Chemical formula 6:

[0111]

[0112] In formula (2),

[0113] R 2It is a straight-chain alkylene group having 1 to 20 carbon atoms.

[0114] Thereby, the strength of the shoe press belt 1 can be further improved while suppressing an increase in the viscosity of the obtained polyurethane composition and suppressing unevenness in strength between the components of the shoe press belt 1 .

[0115] As mentioned above, R 2 is a straight-chain alkylene group having 1 to 20 carbon atoms. 2 Examples thereof include methylene, vinyl, n-propenyl, n-butenyl, n-pentenyl, n-hexenyl, n-heptenyl, n-octenyl, n-nonenyl, n-decenyl, n-undecenyl, n-dodecenyl, n-tridecenyl, n-tetradecenyl, n-pentadecenyl, n-hexadecenyl, n-heptadecenyl, n-octadecenyl, n-nonadecenyl and n-eicosenyl.

[0116] As mentioned above R 2 The number of carbon atoms in R is 1 or more and 20 or less, preferably 2 or more, and more preferably 3 or more. 2 The number of carbon atoms is preferably 15 or less, more preferably 12 or less.

[0117] Particularly preferably, R 2 is selected from the group consisting of n-butenyl, n-hexenyl, n-nonenyl, n-decenyl, n-undecenyl and n-dodecenyl.

[0118] Furthermore, the ratio of the unit B to the unit A, such as the copolymerization ratio (unit B / unit A (Mol / Mol)), is 5% to 95%, preferably 10% to 90%.

[0119] The polycarbonate diol X having the above-mentioned units A and B is represented by, for example, the following formula (4).

[0120] Chemical formula 7:

[0121] HO-A m -B n -R 6 OH (4),

[0122] In formula (4), A represents each occurrence of unit A independently, B represents each occurrence of unit B independently, M and n are each independently an integer of 1 to 40, R 6 For R 1 or R 2 .

[0123] Preferably, m and n are each independently an integer of 1 to 34, more preferably an integer of 1 to 29.

[0124] The ratio of m to n represents the ratio (ratio of number) of the groups of A to B. m / n is not particularly limited, and is, for example, 0.01 to 30, preferably 0.02 to 19, and more preferably 0.10 to 10.

[0125] Furthermore, in the polycarbonate diol X represented by the formula (4), the arrangement of the unit A and the unit B is not particularly limited. That is, the polycarbonate diol X represented by the formula (4) may be a random copolymer, an alternating copolymer, or a block copolymer. Furthermore, the polycarbonate diol X represented by the formula (4) may contain multiple types of units A and / or multiple types of units B.

[0126] In addition to the above-mentioned units A and B, the polycarbonate diol X may further contain a unit in which the alkylene group is a cyclic alkylene group. Such a cyclic alkylene group may be a group having an alicyclic group such as a cyclopentane ring, a cyclohexane ring, a cycloheptane ring or a cyclooctane ring. In this case, the cyclic alkylene group is directly bonded to the adjacent oxygen atom from the alicyclic group or through an alkylene group having 1 to 3 carbon atoms substituted by an alicyclic group. Examples of such a cyclic alkylene group include 1,4-cyclohexanediylbismethylene.

[0127] Furthermore, the polycarbonate diol X can be prepared by using a 1 or R 2 The alkylene glycol of the present invention is obtained by reacting with a carbonate such as diphenyl carbonate. 1 In the case of being selected from 3-methylpentenyl, 2,2-dimethylpropenyl, 2-methyloctenyl, 2-butyl-2-ethylpropenyl and 1,4-cyclohexanediylbismethylene, the polycarbonate diol X can be obtained by synthesizing the polycarbonate diol using a diol selected from 3-methylpentanediol, neopentyl glycol, 2-methyloctanediol, 2-butyl-2-ethylpropanediol and 1,4-cyclohexanedimethanol.

[0128] The number average molecular weight of the polycarbonate diol X is not particularly limited, and may be, for example, 250 to 4000, preferably 500 to 3000. The number average molecular weight of the polycarbonate diol may be calculated, for example, by measuring a hydroxyl value.

[0129] Specifically, first, the hydroxyl value of the polycarbonate diol X is measured. The hydroxyl value of the polycarbonate diol X can be measured according to JIS K1557-1: 2007. On the other hand, the hydroxyl value (MgKOH / g) of the polycarbonate diol X can also be expressed as Formula I below.

[0130] (Hydroxyl value of polycarbonate diol X (MgKOH / g)) = 56110 / (number average molecular weight of polycarbonate diol X) × (average number of hydroxyl groups per molecule of polycarbonate diol X) (I)

[0131] Here, the average number of hydroxyl groups per molecule of the polycarbonate diol X is estimated to be 2.0. Therefore, the number average molecular weight of the polycarbonate diol X can be expressed as the following formula (II).

[0132] (Number average molecular weight of polycarbonate diol X) = 112220 / (hydroxyl value of polycarbonate diol X (MgKOH / g)) (II)

[0133] In the above formula (II), the number average molecular weight of the polycarbonate diol X can be calculated by substituting the hydroxyl value of the polycarbonate diol X obtained in the hydroxyl value measurement. Also, the polycarbonate diols other than the polycarbonate diol X can be calculated in the same manner.

[0134] The amount of the polycarbonate diol X to be added is not particularly limited, but is preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 80% by mass or less, relative to the total resin weight of the portion where the polycarbonate diol X is used. This further improves the strength of the shoe press belt 1 and further suppresses uneven strength between components of the shoe press belt 1. The above-mentioned amount is a ratio of the amount of resin excluding the inorganic filler described later in the resin 23.

[0135] When forming the resin 23 of the first resin layer 20, there is no particular limitation on the time of adding the polycarbonate diol X. For example, the polycarbonate diol X may be added at the following times (i) to (iv). The components of the resin 23 are described below for each of the cases (i) to (iv).

[0136] (i) In the case of containing urethane prepolymer

[0137] For example, polycarbonate diol X can also be used as a component of urethane prepolymer. Specifically, the resin 23 may be a polyurethane resin obtained by reacting a urethane prepolymer having an isocyanate group including one or more polycarbonate diols X as a component with a curing agent having an active hydrogen group.

[0138] That is, in this case, the urethane prepolymer can also be obtained by reacting a polyisocyanate compound with a polyol compound containing one or more polycarbonate diols X. Thus, a relatively large amount of polycarbonate diol X can be blended, and the strength of the shoe press belt 1 can be further improved.

[0139] In this case, there is no particular limitation on the polyisocyanate compound constituting the urethane prepolymer. For example, one or more polyisocyanate compounds selected from aromatic polyisocyanates and aliphatic polyisocyanates can be used. Preferably, 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), 4,4'-methylenebis(phenyl isocyanate) (MDI), p-phenylene diisocyanate (PPDI), dimethyl diphenyl diisocyanate (TODI), 1,5-naphthalene diisocyanate, 4,4-dibenzyl diisocyanate can be used. The invention relates to polyisocyanate compounds comprising diisocyanate (DBDI), 1,6-hexamethylene diisocyanate (HDI), 1,5-pentamethylene diisocyanate, 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane (IPDI), dicyclohexylmethane-4,4'-diisocyanate (H12MDI), xylylene diisocyanate (XDI), cyclohexane diisocyanate (CHDI), 1,4-bis(isocyanatomethyl)cyclohexane (H6XDI) and tetramethylxylylene diisocyanate (TMXDI) and polymethylene polyphenyl polyisocyanate (Polymeric MDI) and a polyisocyanate compound comprising a compound selected from these mixtures.

[0140] In order to further suppress the imbalance between the components of the obtained resin 23, it is particularly preferred that the polyisocyanate compound contains one or more selected from p-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate.

[0141] Furthermore, the polyol compound includes the above-mentioned polycarbonate diol X, but may also include other polyol compounds. There is no particular limitation on such polyol compounds, and for example, polyester polyols such as polycaprolactone polyol, polyethylene adipate, etc., polyether polyols such as polyethylene glycol, polyoxypropylene glycol, polyhexamethylene ether glycol, polytetramethylene ether glycol (PTMG), etc., long-chain polyol compounds such as silicon polyols such as linear aliphatic polycarbonate diol, polyether carbonate diol, trimethylolpropane, polybutadiene polyol, perfluoropolyether polyol, silicon diol, etc. may be included, and one of these may be used alone or two or more may be used in combination.

[0142] For example, examples of the linear aliphatic polycarbonate diol include polymethylene carbonate diol, polyethylene carbonate diol, polypropylene carbonate diol, polybutylene carbonate diol, polypentamethylene carbonate diol, polyhexamethylene carbonate diol, polyheptamethylene carbonate diol and polyoctamethylene carbonate diol.

[0143] In order to improve the hydrolysis resistance of the resin 23 and further improve the durability of the shoe press belt 1, in addition to the polycarbonate diol X represented by the above formula (1), the polyol compound preferably contains a polyether polyol and / or a linear aliphatic polycarbonate diol, more preferably, contains polytetramethylene ether glycol and / or polyhexamethylene carbonate diol.

[0144] Furthermore, when the urethane prepolymer contains a polyol compound other than the above-mentioned polycarbonate diol X, the ratio of the polycarbonate diol X in the urethane prepolymer relative to all polyol compounds is, for example, 10 mass percent or more and less than 90 mass percent, preferably 25 mass percent or more and 80 mass percent or less.

[0145] The curing agent having an active hydrogen group is not particularly limited, and a curing agent containing one or more compounds selected from the group consisting of polyol compounds and polyamines can be used.

[0146] As the polyol compound that can be contained in the curing agent, in addition to the above-mentioned long-chain polyol compounds, various aliphatic polyol compounds and various alicyclic or aromatic polyol compounds can be used.

[0147] The aliphatic polyol compound is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,3-butylene glycol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and the like. Alkylene glycol compounds such as 1,2-diol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecandiol, 1,18-octadecanediol, 1,20-eicosandiol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,8-octanediol, or glycerol, ditrimethylolpropane, trimethylolpropane (TMP), pentaerythritol, dimethylolpropionic acid (DHPA), and the like.

[0148] The alicyclic polyol compound is not particularly limited, and examples thereof include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.

[0149] There is no particular limitation on the aromatic polyol compound, and examples thereof include hydroquinone di-β-hydroxyethyl ether (HQEE), hydroxyphenyl ether resorcinol (HER), 1,3-bis(2-hydroxyethoxybenzene), 1,4-bis(2-hydroxyethoxybenzene), bisphenol A, bisphenol A alkylene oxide adducts, bisphenol S, bisphenol S alkylene oxide adducts, and the like.

[0150] The polyamine is not particularly limited, and examples thereof include hydrazine, ethylenediamine, 4,4'-methylene-bis-(2-chloroaniline) (MOCA), dimethylthiotoluenediamine (DMTDA), diethylthiotoluenediamine, diethyltoluenediamine (DETDA), trimethylene glycol di(p-aminobenzoate) (TMAB), 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) (MCDEA), 4,4'-methylene-bis-(2,6-diethylaniline) (MDEA), triisopropanolamine (TIPA), p-bis(aminocyclohexyl)methane (PACM), naphthalene-1,5-diamine, xylene diamine, phenylenediamine, toluene-2,4-diamine, tert-butyltoluenediamine, and 1,2-bis(2-aminophenylthioethane).

[0151] In the above content, in order to further improve the strength of the obtained resin 23 and further suppress the strength imbalance between the parts of the shoe press belt 1, preferably, the curing agent contains an aliphatic polyol compound and / or a polyamine, more preferably, contains an alkylene glycol compound, dimethylthiotoluenediamine and / or diethyltoluenediamine, more preferably, contains 1,4-butanediol, dimethylthiotoluenediamine and / or diethyltoluenediamine.

[0152] Furthermore, the resin 23 may contain one or more inorganic fillers such as titanium oxide, kaolin, clay, talc, diatomaceous earth, calcium carbonate, calcium silicate, magnesium silicate, silicon dioxide, mica, etc. in combination.

[0153] (ii) When contained in a curing agent

[0154] Furthermore, for example, the polycarbonate diol X can also be used as a component of the curing agent. Specifically, the resin 23 can be a polyurethane resin obtained by reacting a urethane prepolymer having an isocyanate group with a curing agent having an active hydrogen group containing one or more polycarbonate diols X. As such, by including one or more polycarbonate diols X in the curing agent, the mixed viscosity of the polyurethane composition containing the urethane prepolymer and the curing agent can be reduced. Therefore, the strength of the shoe press belt 1 can be improved while further suppressing the strength imbalance between the components.

[0155] In this case, as the polyisocyanate compound of the urethane prepolymer, for example, various polyisocyanate compounds described in (i) above can be used. Preferably, the polyisocyanate compound comprises one or more selected from p-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate.

[0156] In order to improve the hydrolysis resistance of the resin 23 and further improve the durability of the shoe press belt 1, the polyol compound preferably includes polyether polyol and / or linear aliphatic polycarbonate diol, more preferably polytetramethylene ether glycol and / or polyhexamethylene carbonate diol.

[0157] As described above, in the case of (ii), the curing agent contains one or more polycarbonate diols X. Furthermore, the curing agent may contain other curing agents in addition to one or more polycarbonate diols X. As such a curing agent, the curing agent that can be used in the case of (i) above can be used.

[0158] In this case, in addition to one or more polycarbonate diols X, the curing agent preferably contains an aliphatic polyol compound and / or a polyamine, more preferably, contains an alkylene glycol compound, dimethylthiotoluenediamine and / or diethyltoluenediamine, more preferably, contains 1,4-butanediol, dimethylthiotoluenediamine and / or diethyltoluenediamine.

[0159] Furthermore, when the curing agent contains a curing agent other than one or more polycarbonate diols X, the ratio of the one or more polycarbonate diols X in the curing agent is, for example, 10 mass percent or more and less than 100 mass percent, and preferably 50 mass percent or more and 95 mass percent or less.

[0160] Furthermore, the resin 23 may contain one or more inorganic fillers such as titanium oxide, kaolin, clay, talc, diatomaceous earth, calcium carbonate, calcium silicate, magnesium silicate, silicon dioxide, mica, etc. in combination.

[0161] (iii) When contained in a urethane prepolymer and a curing agent

[0162] Furthermore, the urethane prepolymer and the curing agent may contain one or more polycarbonate diols X as components. Specifically, the resin 23 may be a polyurethane resin obtained by reacting a urethane prepolymer having an isocyanate group containing one or more polycarbonate diols X as components with a curing agent having an active hydrogen group containing one or more polycarbonate diols X.

[0163] In this case, as the polyisocyanate compound of the urethane prepolymer, for example, various polyisocyanate compounds described in (i) above can be used. Preferably, the polyisocyanate compound comprises one or more selected from p-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate.

[0164] Furthermore, in the case of (iii), the urethane prepolymer contains polycarbonate diol X, but may further contain other polyol compounds. In order to further suppress uneven strength between parts of the shoe press belt 1 and further improve the strength of the shoe press belt 1, preferably, the polyol compound contains polyether polyol and / or linear aliphatic polycarbonate diol, more preferably, contains polytetramethylene ether glycol and / or polyhexamethylene carbonate glycol.

[0165] Furthermore, when the urethane prepolymer contains a polyol compound other than the polycarbonate diol X, the ratio of the polycarbonate diol X in the urethane prepolymer relative to all the polyol compounds is, for example, 10 mass percent or more and less than 90 mass percent, preferably 25 mass percent or more and 80 mass percent or less.

[0166] As described above, in the case of (iii), the curing agent contains one or more polycarbonate diols X. Furthermore, the curing agent may contain other curing agents in addition to one or more polycarbonate diols X. As such a curing agent, the curing agent applicable to the case of (i) above can be used.

[0167] In this case, in addition to one or more polycarbonate diols X, the curing agent preferably contains an aliphatic polyol compound and / or a polyamine, more preferably, contains an alkylene glycol compound, dimethylthiotoluenediamine and / or diethyltoluenediamine, more preferably, contains 1,4-butanediol, dimethylthiotoluenediamine and / or diethyltoluenediamine.

[0168] Furthermore, when the curing agent contains a curing agent other than one or more polycarbonate diols X, the ratio of the one or more polycarbonate diols X in the curing agent is, for example, 10 mass percent or more and less than 100 mass percent, and preferably 50 mass percent or more and 95 mass percent or less.

[0169] Furthermore, the resin 23 may contain one or more inorganic fillers such as titanium oxide, kaolin, clay, talc, diatomaceous earth, calcium carbonate, calcium silicate, magnesium silicate, silicon dioxide, mica, etc. in combination.

[0170] (iv) In the case of forming the polyurethane resin by a one-step method

[0171] In the above (i) to (iii), the polyurethane resin is formed by curing the urethane prepolymer with a curing agent, but the polyurethane resin can also be formed by a one-step process.

[0172] In this case, the polyurethane resin as the resin 23 of the first resin layer 20 can be formed by curing a polyurethane composition obtained by mixing one or more polycarbonate diols X and the polyisocyanate compound described in detail in (i) above, and the polyol compound, curing agent and / or inorganic filler as required as described in detail in the description of the urethane prepolymer.

[0173] Furthermore, for each of (i) to (iv), in the case where any one of the resin 33 of the second resin layer 30 and the resin 13 of the reinforcing fiber base material layer 10 contains a polyurethane resin formed using polycarbonate diol X, the first resin layer 20 may not contain the polyurethane resin. In this case, the material of the resin 23 of the first resin layer 20 may be a combination of one or more thermosetting resins such as polyurethane resin (however, not containing polycarbonate diol X as a component), epoxy resin, acrylic resin, etc., or thermoplastic resins such as polyamide, polyarylate, polyester, etc.

[0174] As the resin 33 constituting the second resin layer 30, one or more of the resin materials that can be used for the first resin layer 20 as described above can be used in combination. The resin 33 constituting the second resin layer 30 may be the same as or different from the resin 23 constituting the first resin layer 20 in type and composition. In particular, from the viewpoint of improving the durability of the second resin layer 30 and the viewpoint of improving the resin production efficiency, it is preferred that the resin 33 constituting the second resin layer 30 is the same as the resin 23 of the first resin layer 20.

[0175] Furthermore, preferably, the second resin layer 30 includes a polyurethane resin formed by using polycarbonate diol X. The second resin layer 30 constitutes the inner peripheral surface 31 of the shoe press belt 1. In the shoe press belt 1, the inner peripheral surface 31 is a portion that is easily damaged due to friction with the shoe when the shoe press belt 1 is used or due to bending fatigue of the shoe press belt 1. Therefore, by including the polyurethane resin formed by using polycarbonate diol X in the second resin layer 30 constituting the inner peripheral surface 21 of the shoe press belt 1, the durability of the shoe press belt 1 is improved.

[0176] As the resin 13 constituting the reinforcing fiber base material layer 10, one or more of the resin materials that can be used for the first resin layer 20 as described above can be used in combination. The resin 13 constituting the reinforcing fiber base material layer 10 may be the same as or different from the resin 23 constituting the first resin layer 20 in type and composition. In particular, from the viewpoint of improving the resin production efficiency, the resin 13 constituting the reinforcing fiber base material layer 10 may be the same as the resin 23 of the first resin layer 20.

[0177] Furthermore, preferably, the reinforcing fiber base material layer 10 includes a polyurethane resin formed by using polycarbonate diol X. Thus, the durability of the shoe press belt 1 is improved.

[0178] The dimensions of the shoe press belt 1 as described above are not particularly limited and can be appropriately set according to its application.

[0179] For example, the width of the shoe press belt 1 is not particularly limited, but may be 700 mm to 13500 mm, and preferably, may be 2500 mm to 12500 mm.

[0180] Also, for example, the length (circumference) of the shoe press belt 1 is not particularly limited, but may be 150 cm to 1500 cm, and preferably, may be 200 cm to 1100 cm.

[0181] Also, the thickness of the shoe press belt 1 is not particularly limited, but may be, for example, 1.5 mm to 7.0 mm, preferably, 2.0 mm to 6.0 mm.

[0182] Furthermore, the thickness of each portion of the shoe press belt 1 may be different or the same.

[0183] As described above, in the shoe press belt 1 according to the present embodiment, at least one of the resin 13 of the reinforcing fiber base layer 10, the resin 23 of the first resin layer 20, and the resin 33 of the second resin layer 30 includes a polyurethane resin containing the above-mentioned polycarbonate diol X as a component. Therefore, the shoe press belt 1 suppresses uneven strength between components and is excellent in strength.

[0184] Next, a shoe press belt according to another embodiment of the present embodiment will be described. Figure 2 This is a cross-sectional view of a shoe press belt according to another embodiment of the present invention. Hereinafter, the differences from the above embodiment will be mainly described, and the description of the same matters will be omitted.

[0185] like Figure 2 As shown, the shoe press belt 1A has a plurality of drainage grooves 25 formed on the outer peripheral surface 21 of the first resin layer 20A. Since the shoe press belt 1A has the drainage grooves 25, when the shoe press belt is used With 1A,Remove more water from the loaded wet paper.

[0186] The form of the drainage groove 25 is not particularly limited, but generally, a plurality of continuous grooves parallel to the machine longitudinal direction of the shoe press belt 1A are generally formed. For example, the width of the groove can be set to 0.5 mm to 2.0 mm, the depth of the groove can be set to 0.4 mm to 2.0 mm, and the number of grooves can be set to 5 to 20 per inch. In addition, the cross-sectional shape of the drainage groove 25 can be appropriately set to a rectangular, trapezoidal, U-shaped, or circular at the welded portion and the portion where the groove bottom is connected to the groove wall.

[0187] Furthermore, the shapes of the drainage grooves 25 can be the same in terms of groove width, depth, number and cross-sectional shape, or can be combined to form different shapes. Further, the drainage grooves 25 can form a plurality of grooves that are discontinuous or parallel to the machine transverse direction.

[0188] As described above, in the shoe press belt 1A according to the present embodiment, at least one of the resin 13 of the reinforcing fiber base layer 10, the resin 23 of the first resin layer 20A, and the resin 33 of the second resin layer 30 contains the above-mentioned polycarbonate diol X as a component. Therefore, the shoe press belt 1A suppresses uneven strength between components and is excellent in strength.

[0189] 2. Preparation method of shoe-shaped press belt

[0190] Next, a preferred embodiment of a method for producing a shoe press belt of the present invention will be described. Figure 3 to Figure 5 It is a schematic diagram for explaining a preferred embodiment of a method for producing a shoe press belt.

[0191] The method for producing a shoe press belt according to the present invention is a method for producing a shoe press belt for a papermaking machine, comprising the steps of forming a resin layer containing a polyurethane resin by solidifying a polyurethane raw material,

[0192] The polyurethane raw material contains, as a structural unit, a polycarbonate diol containing one or more units A represented by the following formula (1).

[0193] Chemical formula 8:

[0194]

[0195] In formula (1),

[0196] R 1 It is a branched alkylene group having 3 or more and 20 or less carbon atoms.

[0197] Furthermore, the method for manufacturing a shoe press belt according to an embodiment of the present invention includes a resin layer forming step of forming the first resin layer 20 , the reinforcing fiber base material layer 10 , and the second resin layer 30 .

[0198] Specifically, in this step, a laminated body is formed, which includes a reinforcing fiber base material layer 10 having an annular and belt-shaped reinforcing fiber base material 11 buried in a resin 13, and first and second resin layers 20 and 30 stacked on both sides thereof as resin layers.

[0199] Such a laminate can be formed by any method, but in this embodiment, the second resin layer 30 is formed. Next, the reinforcing fiber substrate 11 is arranged on one surface of the second resin layer 30, and the resin material is applied, impregnated and penetrated in the reinforcing fiber substrate 11, thereby forming a laminate in which the reinforcing fiber substrate layer 10 and the second resin layer 30 are integrated. Next. The first resin layer 20 is formed on the surface of the reinforcing fiber substrate layer 10 facing the contact surface between the reinforcing fiber substrate layer 10 and the second resin layer 30.

[0200] Specifically, for example, first, Figure 3 As shown, a resin precursor layer as the second resin layer 30 is formed by applying a resin material to the surface of the mandrel 110 to a thickness of 0.8 to 3.5 mm while the mandrel 110 coated with a release agent on the surface is rotated. Next, the temperature of the resin precursor layer is increased to 40 to 140° C. and pre-cured for 0.5 to 1 hour to form the second resin layer 30.

[0201] Next, a reinforcing fiber substrate 11 (not shown) is disposed on the pre-cured second resin layer 30. Figure 4 As shown, the mandrel 110 is rotated, and the resin material forming the reinforcing fiber substrate layer 10 is applied to 0.5 to 2.0 mm, impregnated and penetrated into the reinforcing fiber substrate, and contacted with the second resin layer 30, thereby forming a laminated body in which the reinforcing fiber substrate layer 10 and the second resin layer 30 are integrated.

[0202] Afterwards, if Figure 5 As shown, a resin material for forming the first resin layer 20 is applied and impregnated onto the surface of the reinforcing fiber substrate layer 10 to form a thickness of 1.5 to 4 mm while rotating the mandrel 110, and a resin precursor layer is formed as the first resin layer 20. Next, the resin precursor layer is heat-cured at 70 to 140° C. for 2 to 20 hours to form a laminated body in which the first resin layer 20, the reinforcing fiber substrate layer 10, and the second resin layer 30 are laminated.

[0203] The resin material may be applied by any method, but in the present embodiment, the resin material is discharged from the injection molding nozzle 130 while the mandrel 110 is rotated, and the supplied resin material is uniformly applied using the coating rod 120 .

[0204] Among them, at least one of the resin 13 of the reinforcing fiber base material layer 10, the resin 23 of the first resin layer 20, and the resin 33 of the second resin layer 30 includes a polyurethane resin containing the above-mentioned polycarbonate diol X as a component. As described above, when the above-mentioned polycarbonate diol X is included as a component, the viscosity increase of the polyurethane composition (resin material) can be suppressed. Therefore, a uniform polyurethane resin layer can be formed.

[0205] Furthermore, the heating method is not particularly limited, and for example, a far infrared heater or the like can be used.

[0206] The obtained laminate is subjected to grinding or polishing on the outer peripheral surface 21 and the inner peripheral surface 31 as required, and the ends in the width direction are appropriately cut and adjusted to obtain the shoe press belt 1. The shoe press belt 1 is produced through the above steps.

[0207] Furthermore, in the case of producing the shoe press belt 1A, the laminate formed in the above-mentioned resin layer forming step may further have the drainage grooves 25 formed on the outer peripheral surface 21 as shown in the following step.

[0208] Such a drainage ditch 25 can be formed by any method, but, for example, the outer surface of the laminate obtained as described above is ground or polished so as to have the desired thickness of the boot-shaped press belt 1 (not shown), and then a groove processing device having a plurality of disc-shaped rotating blades attached thereto can be brought into contact with the outer peripheral surface 21 while rotating the mandrel 110 to form the drainage ditch 25.

[0209] Furthermore, the method for preparing the shoe press belt in the above-mentioned embodiment has been described as a method for preparing a mandrel (single roller). However, as another embodiment, the following two-roll preparation method may be adopted. First, an annular reinforcing fiber substrate 11 is suspended on two rollers arranged in parallel, and is coated, impregnated, and laminated on its reinforcing fiber substrate 11 with a resin to form a second resin layer 30 together with the reinforcing fiber substrate layer 10. Next, it is reversed, and a first resin layer 20 is formed on the surface of the inverted reinforcing fiber substrate layer 10. Thus, a shoe press belt 1 can be obtained. Furthermore, the formation order of each resin layer can be arbitrary.

[0210] Although the present invention has been described in detail based on the preferred embodiments above, the present invention is not limited thereto, and each structure may be replaced with an arbitrary structure that can exhibit the same function, or an arbitrary structure may be added.

[0211] Example

[0212] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

[0213] 1. Preparation of shoe-shaped press belt and polyurethane sheet samples

[0214] Before preparing the shoe press belt, first, the polycarbonate diol shown in Table 1 and the polytetramethylene ether glycol shown in Table 2 were prepared, and resin materials (polyurethane compositions) having the compositions of Examples 1 to 6 and Comparative Examples 1 to 4 shown in Table 3 were obtained by using these. Furthermore, a urethane prepolymer and a curing agent were blended with all the resin materials so that the blending ratio of [H] / [NCO] was 0.95.

[0215] Next, a shoe press belt was prepared by the following method using the resin materials of Examples 1 to 6 and Comparative Examples 1 to 4.

[0216] On the surface of a rotatable mandrel with a diameter of 1500 mm, the resin materials of Examples 1 to 6 and Comparative Examples 1 to 4 were applied to a thickness of 1.4 mm through an injection molding nozzle that could move parallel to the rotation axis of the mandrel while the mandrel was rotated by an appropriate driving device to form an uncured shoe side resin layer (second resin layer). Thereafter, the mandrel was rotated continuously at room temperature for 10 minutes, and heated to 140° C. by a heating device installed on the mandrel, and the shoe side resin layer was pre-cured at 140° C. for 1 hour.

[0217] Next, the warp is clamped with the weft, and a layer of lattice material with no gaps between the weft and the warp is bonded by a polyurethane resin adhesive at the intersection of the weft and the warp, so that the weft is aligned along the axial direction of the mandrel. The weft of the lattice material is a 5000 dtex multifilament twisted yarn of polyethylene terephthalate fiber, and the warp is a 550 dtex multifilament of polyethylene terephthalate fiber. In addition, the warp density is 1 thread / cm, and the weft density is 4 threads / cm.

[0218] Next, a 6700 dtex multifilament of polyethylene terephthalate fiber was spirally wound at a pitch of 30 threads / 5 cm on the periphery of the lattice material to form a filament winding layer, and the lattice material and the filament winding layer formed a reinforcing fiber substrate. Thereafter, a resin material (resin materials of Examples 1 to 6 and Comparative Examples 1 to 4) the same as the resin material of the shoe side resin layer was applied to close the gaps in the reinforcing fiber substrate, forming a laminated body composed of the reinforcing fiber substrate layer and the shoe side resin layer integrated.

[0219] Next, a resin material identical to the resin material of the reinforcing fiber base material layer and the shoe side resin layer (resin materials of Examples 1 to 6 and Comparative Examples 1 to 4) is applied to a thickness of about 2.5 mm from above the reinforcing fiber base material layer while rotating the mandrel through an injection molding nozzle that can move parallel to the rotation axis of the mandrel, thereby forming an uncured felt side resin layer (first resin layer).

[0220] Next, the mandrel was left at room temperature for 40 minutes while being rotated, and each resin layer was heated to 140° C. by a heating device installed on the mandrel, and heat-cured at 140° C. for 4 hours. Thus, a laminated body including the felt side resin layer, the reinforcing fiber base material layer, and the shoe side resin layer was formed.

[0221] Thereafter, the felt contact surface of the resin layer on the felt side was polished so that the total thickness became 5.2 mm, thereby obtaining a laminated body.

[0222] Shoe press belts according to Examples 1 to 6 and Comparative Examples 1 to 4 were obtained through the above steps. The hardness of the obtained shoe press belts was evaluated. In addition, in order to evaluate the breaking strength and imbalance in the tensile test, polyurethane sheet samples with a thickness of 1.0 mm were cut out from 20 random locations of the resin layer on the felt side.

[0223] 2. Evaluation

[0224] 2.1. Prepolymer viscosity

[0225] The viscosity of the prepolymer used as the resin material of Examples 1 to 6 and Comparative Examples 1 to 4 was measured. The viscosity of the prepolymer was measured at 50° C. and 80° C. using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd., product name: TVB-10H). The H3 rotor was used as the rotor, and the measurement results showed that the rotation number was 50 rpm in the case of 200 to 2000 mPa·s, and the rotation number was 5 rpm in the case of 2000 to 20000 mPa·s.

[0226] 2.2. Hardness evaluation

[0227] The hardness of the outer peripheral surface of the shoe press belt according to Examples 1 to 6 and Comparative Examples 1 to 4 was measured. Specifically, the surface hardness of the felt-side resin layer was measured using a spring hardness tester type A in accordance with JIS K 6301:1995.

[0228] 2.3. Evaluation of breaking strength of tensile test

[0229] For the breaking strength, a universal tensile tester was used as the tester, a dumbbell No. 3 specimen specified in JIS K 6251 was used as the sample shape, and the breaking strength was measured at a tensile speed of 500 mm / min, and the stress (MPa) when the specimen broke was evaluated. Each embodiment and comparative example was measured 20 times and expressed as an average value.

[0230] 2.4. Unbalanced evaluation of breaking strength

[0231] The unevenness of the breaking strength was evaluated by calculating the standard deviation of 20 breaking strength measurements in the tensile test.

[0232] The above evaluation results are shown in Table 3 together with the compositions of the resin materials of Examples 1 to 6 and Comparative Examples 1 to 4.

[0233] In Table 3, "MDI" represents 4,4'-methylenebis(phenyl isocyanate), "H6XDI" represents 1,4-bis(isocyanatomethyl)cyclohexane, "PPDI" represents p-phenylene diisocyanate, "TDI" represents a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, "BD" represents 1,4-butanediol, and "DMTDA" represents dimethylthiotoluenediamine.

[0234] Also, regarding the number average molecular weight of the polycarbonate diols in Table 1, the hydroxyl value of each polycarbonate diol was measured and the number average molecular weight of the above formula (II) was calculated based on the obtained hydroxyl value. The same is true for the polytetramethylene ether glycol in Table 2.

[0235] Table 1

[0236]

[0237] Table 2

[0238] Polytetramethylene ether glycol Number average molecular weight Hydroxyl value (mg KOH / g) PTMG1 648 173.1 PTMG2 1039 108.0 PTMG3 1990 56.4

[0239] Table 3

[0240]

[0241]

[0242] As shown in Table 3, the shoe press belts according to Examples 1 to 6 suppressed uneven strength among parts and were excellent in strength compared to the shoe press belts according to Comparative Examples 1 to 3. In particular, in Examples 1 and 2 in which only a specific polycarbonate diol was blended as the polyol compound in the prepolymer, the strength of the shoe press belt was improved compared to the other examples. In addition, in Examples 3, 4, and 6 in which a specific polycarbonate diol was blended in the curing agent, uneven strength among parts of the shoe press belt was further suppressed compared to the other examples.

[0243] Furthermore, the shoe press belt of Comparative Example 4 using a linear aliphatic polycarbonate diol is excellent in strength, but has a large strength imbalance between parts. Therefore, the shoe press belt of Comparative Example 4 may be damaged from a weak portion, and the durability of the shoe press belt cannot be improved.

Claims

1. A shoe press belt for a papermaking machine, characterized in that having at least one resin layer comprising a polyurethane resin, The polyurethane resin comprises, as a component, a polycarbonate diol containing one or more units A represented by the following formula (1), Chemical formula 1: In formula (1), R 1 is a branched alkylene group having 3 or more and 20 or less carbon atoms; The polycarbonate diol further comprises one or more units B represented by the following formula (2): Chemical formula 2: In formula (2), R 2 is a straight-chain alkylene group having 1 to 20 carbon atoms; The ratio of the unit B to the unit A is 5% or more and 95% or less in terms of a copolymerization ratio of unit B / unit A (mol / mol).

2. The shoe press belt according to claim 1, characterized in that R 1 Selected from the group consisting of 3-methylpentenyl, 2,2-dimethylpropenyl, 2-methyloctenyl, 2-butyl-2-ethylpropenyl and 2,2,4-trimethyl-1,6-hexenyl.

3. The shoe press belt according to claim 1, characterized in that R 2 is selected from the group consisting of n-butenyl, n-hexenyl, n-nonenyl, n-decenyl, n-undecenyl and n-dodecenyl.

4. The shoe press belt according to claim 1, characterized in that The above-mentioned polyurethane resin is obtained by reacting a urethane prepolymer having an isocyanate group containing one or more of the above-mentioned polycarbonate diols as a component with a curing agent having an active hydrogen group.

5. The shoe press belt according to claim 4, characterized in that The above-mentioned urethane prepolymer is obtained by reacting a polyisocyanate compound with a polyol compound, wherein the above-mentioned polyisocyanate compound includes one or more selected from p-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), 1,4-bis(isocyanatomethyl)cyclohexane, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, and the above-mentioned polyol compound includes one or more of the above-mentioned polycarbonate diols.

6. The shoe press belt according to claim 5, characterized in that The above-mentioned polyol compound further includes polytetramethylene ether glycol and / or polyhexamethylene carbonate glycol.

7. The shoe press belt according to claim 4, characterized in that The curing agent contains one or more of the polycarbonate diols.

8. The shoe press belt according to claim 1, characterized in that The polyurethane resin is obtained by reacting a urethane prepolymer having an isocyanate group with a curing agent having an active hydrogen group containing one or more of the polycarbonate diols.

9. The shoe press belt according to claim 8, characterized in that The curing agent further comprises an alkylene glycol compound, dimethylthiotoluenediamine and / or diethyltoluenediamine.

10. The shoe press belt according to claim 8, characterized in that The curing agent comprises 1,4-butanediol, dimethylthiotoluenediamine and / or diethyltoluenediamine.

11. The shoe press belt according to claim 9, characterized in that The urethane prepolymer is obtained by reacting a polyisocyanate compound with a polyol compound containing a polyether polyol compound and / or a linear aliphatic polycarbonate diol.

12. A shoe press belt according to any one of claims 1 to 11, characterised in that The resin layer has a first layer constituting the outer peripheral surface of the shoe press belt, The first layer includes the polyurethane resin.

13. A shoe press belt according to any one of claims 1 to 11, characterised in that The resin layer has a second layer constituting the inner peripheral surface of the shoe press belt, The second layer includes the polyurethane resin.

14. A method for preparing a shoe press belt for a papermaking machine, characterized in that: The method comprises the steps of forming a resin layer comprising a polyurethane resin by curing a polyurethane raw material, The polyurethane raw material comprises, as a component, a polycarbonate diol containing one or more units A represented by the following formula (1), Chemical formula 3: In formula (1), R 1 is a branched alkylene group having 3 or more and 20 or less carbon atoms; The polycarbonate diol further comprises one or more units B represented by the following formula (2): Chemical formula 2: In formula (2), R 2 is a straight-chain alkylene group having 1 to 20 carbon atoms; The ratio of the unit B to the unit A is 5% or more and 95% or less in terms of a copolymerization ratio of unit B / unit A (mol / mol).

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