WO2015159787A1

WO2015159787A1 - Husking roll

Info

Publication number: WO2015159787A1
Application number: PCT/JP2015/061072
Authority: WO
Inventors: 岩崎　成彰; 勇喜阿部; 三生堀内
Original assignee: バンドー化学株式会社
Priority date: 2014-04-16
Filing date: 2015-04-09
Publication date: 2015-10-22
Also published as: KR20190018529A; KR20160145125A; CN106457254B; JP2015202480A; KR102061495B1; JP5707522B1; CN106457254A

Abstract

The purpose of the present invention is to provide a husking roll that has excellent durability, is unlikely to expand during use, and is resistant to discoloration during storage. This husking roll comprises a core material section and a rubber layer laminated on to the outer circumferential surface of the core material section. The rubber layer comprises a cured product of a heat-curable urethane composition containing a polyol component, an isocyanate component, and a cross-linking agent. The polyol component is a polyester polyol; the isocyanate component is TDI and/or MDI; and the cross-linking agent is 1,4-butanediol and 1,4-bis (β-hydroxyethoxy) benzene.

Description

Hulling roll

The present invention relates to a hulling roll.

A threshing roll is attached to the threshing machine for agriculture. This hulling roll is used by arranging two hulling rolls as a pair and arranging the hulling rolls so as to have a predetermined interval. In the pair of rice hull rolls arranged in this way, the rice hulls are removed by putting rice grains (rice with rice hulls) into the gaps between the rice hull rolls while rotating each rice hull roll at different peripheral speeds. And brown rice.

As such a roll member, a roll member composed of a cylindrical shin material portion and a rubber layer provided in the periphery thereof is generally used (for example, see Patent Document 1).
The rubber layer is formed using a synthetic rubber such as nitrile rubber (NBR) or styrene / butadiene rubber (SBR).

JP 2001-029809 A

Since the hulling roll has the above-described configuration, the rubber layer gradually wears with the removal of the chaff, and if the thickness of the rubber layer becomes thin due to wear, the performance as a hulling roll cannot be exhibited. . Therefore, when the thickness of the rubber layer reaches the set value, it is necessary to replace the hulling roll.
Here, the conventional hulling roll has a problem that the durability (abrasion resistance) of the rubber layer is insufficient, and the hulling roll must be frequently replaced.
In addition, as described above, the hulling machine uses a pair of hulling rolls rotated at different peripheral speeds, so that the hulling roll (main roll) on the side with the higher rotation speed is the hulling on the side with the lower rotation speed. Compared with the roll (sub-roll), it is worn out greatly. For this reason, the main roll and the sub roll are usually used two to three times before the rubber layer thickness reaches a set value due to wear. And in the conventional hulling roll as mentioned above, there also existed a problem that the main roll and the subroll had to be replaced | exchanged frequently.

Therefore, the present inventors have studied to provide a hulling roll excellent in durability, and a hulling roll having a polyurethane rubber layer is more durable than a hulling roll having a rubber layer made of NBR or SBR. It was found to be excellent in properties.
However, in the hulling roll provided with the polyurethane rubber layer, the rubber layer expands as the temperature of the rubber layer increases during use, and the gap between the hulling rolls cannot be maintained. Contact with each other and heat is greatly generated due to a difference in peripheral speed between the hulling rolls. And since calorific value became large, the rubber layer made from polyurethane melted, and the hulling performance fell, and it might be damaged further. In addition, the rubber layer may be discolored during storage, and the appearance may cause the deterioration of the hulling roll.

Therefore, the present inventors have further studied and completed a hulling roll having a rubber layer that is excellent in durability (abrasion resistance), hardly expands during use, and hardly discolors during storage.
The hulling roll of the present invention is a hulling roll comprising a shin material part and a rubber layer laminated on the outer peripheral surface of the shin material part,
The rubber layer is composed of a cured product of a thermosetting urethane composition containing a polyol component, an isocyanate component, and a crosslinking agent,
The polyol component is a polyester polyol,
The isocyanate component is TDI and / or MDI,
The cross-linking agent is 1,4-butanediol and 1,4-bis (β-hydroxyethoxy) benzene.

In the hulling roll, the isocyanate component is preferably MDI.
In the hulling roll, the rubber layer preferably has a JIS-A hardness at 20 ° C. of 85 ° or more and less than 99 °.
Furthermore, in the hulling roll, the rubber layer preferably has a DIN wear loss of 60 to 100 mm ³ .

In the hulling roll of the present invention, since the rubber layer is made of a cured product of a specific thermosetting urethane composition, it is exceptionally excellent in durability (wear resistance) and can be used for a long period of time.
Moreover, in the said hulling roll, since it is hard to thermally expand even if the temperature of a rubber layer rises at the time of use, the clearance gap between hulling rolls can be maintained reliably.
Further, the hulling roll is hardly discolored during storage.

(A) is a perspective view schematically showing an example of a hulling roll of the present invention, (b) is a front view of the hulling roll shown in (a), and (c) is an AA view of (a). It is line sectional drawing. It is a schematic diagram for demonstrating the usage method of the hulling roll of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The hulling roll of the present invention is a hulling roll provided with a shin material part and a rubber layer laminated on the outer peripheral surface of the shin material part, and the rubber layer contains a polyol component, an isocyanate component and a crosslinking agent. It consists of the hardened | cured material of a thermosetting urethane composition. Here, the polyol component is a polyester polyol, the isocyanate component is TDI and / or MDI, and the cross-linking agent is 1,4-butanediol and 1,4-bis (β-hydroxyethoxy). ) Benzene.

Fig.1 (a) is a perspective view which shows typically an example of the hulling roll of this invention, (b) is a front view of the hulling roll shown to (a), (c) is A of (a). FIG.
A hulling roll 10 shown in FIGS. 1 (a) to 1 (c) includes a metallic reinforced material portion 11 and a rubber layer 12 laminated on the outer peripheral surface of the reinforced material portion 11.
The shin material part 11 is a cylindrical member provided with an attachment flange 11a for attaching the hulling roll 10 to the hulling machine in the cylinder.
A rubber layer 12 is formed with a uniform thickness on the entire outer peripheral surface of the shin part 11.
The rubber layer 12 is a layer made of a cured product of a specific thermosetting urethane composition containing a polyol component, an isocyanate component, and a crosslinking agent.

Hereinafter, the structural member of the hulling roll of this invention is demonstrated.
As the above-mentioned shin material part, the same sinter material part used in a conventionally known hulling roll can be used. Examples of the material for the shin material part include aluminum, stainless steel, iron, molybdenum, and titanium.
Moreover, the shape and size of the above-mentioned shin material part are not particularly limited, and can be appropriately set according to the specifications of the hulling machine to which the hulling roll is attached and JIS standards (JIS B 9214: rubber roll for hulling) as in the conventional product. Good.

The rubber layer is made of a cured product of a thermosetting urethane composition containing a polyol component, an isocyanate component, and a crosslinking agent. The thermosetting urethane composition contains TDI and / or MDI as the isocyanate component. Therefore, the rubber layer has an excellent effect that it is excellent in durability, hardly thermally expands during use, and further hardly discolored.

Conventionally known TDI can be used as the TDI (tolylene diisocyanate). In the above TDI, the mixing ratio of 2,4-TDI and 2,6-TDI (2,4-TDI / 2,6-TDI) is not particularly limited, but 65/35 to 80/20 (weight ratio) is preferable. Examples of the TDI include T-80 (2,4-TDI / 2,6-TDI = 80/20), T-100 (2,4-TDI / 2,6-TDI = 100/0), T -65 (2,4-TDI / 2,6-TDI = 65/35) or the like can be used.
Of course, various commercial products can be used as the TDI.

The MDI (diphenylmethane diisocyanate or polymethylene polyphenylene polyisocyanate) is not particularly limited, and can be used regardless of whether the molecular weight distribution is wide or narrow. As the MDI, for example, pure MDI (4,4′-MDI), polymeric MDI, or the like can be used.
Of course, various commercial products can be used as the MDI.

The isocyanate group concentration in the thermosetting urethane composition is preferably 1.2 to 4.5% by weight.
If the isocyanate group concentration is less than 1.2% by weight, the abrasion resistance of the cured product may be lowered. On the other hand, if the isocyanate group concentration exceeds 4.5% by weight, the cured product may be too hard.
The said isocyanate group density | concentration (weight%) means the weight ratio of the isocyanate group contained in the total amount of an isocyanate component, a polyol component, and a crosslinking agent.

The polyol component is a polyester polyol. This is because a rubber layer having excellent abrasion resistance can be formed by a high intermolecular force expressed by a highly polar polyester polyol group.

Examples of the polyester polyol include those obtained by reacting dicarboxylic acid and glycol according to a conventional method.
Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, and sebacic acid, and oxycarboxylic acids such as oxybenzoic acid. Examples thereof include acids and ester-forming derivatives thereof.
Of these, adipic acid is preferred, and adipic acid is particularly preferred when 1,4-butanediol is used as the glycol or crosslinking agent. Since the C atom arrangement of adipic acid is the same quadruple arrangement as 1,4-butanediol, it has excellent oriented crystallinity and exhibits a strong intermolecular force by having a crystallized structure. Moreover, since adipic acid is cheap, it is economically excellent.
The said dicarboxylic acid may be used independently and may be used together 2 or more types.

Examples of the glycol include aliphatic glycols such as ethylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and triethylene glycol. Examples include alicyclic glycols such as 1,4-cyclohexanedimethanol, aromatic diols such as p-xylene diol, polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.
As the glycol, an aliphatic glycol is preferable, and ethylene glycol and 1,4-butanediol are more preferable. It is suitable for forming a rubber layer having a JIS-A hardness of about 90 ° and is inexpensive.
The polyester polyol, which is a reaction product of dicarboxylic acid and glycol, has a linear structure, but may be a branched polyester using a trivalent or higher valent ester-forming component.
The above glycols may be used alone or in combination of two or more.

As the polyester polyol, polyethylene adipate polyester polyol, polybutylene adipate polyester polyol, and polyethylene butylene adipate polyester polyol are particularly preferable. It has a molecular structure suitable for forming a rubber layer having a JIS-A hardness of about 90 ° and is inexpensive.

The polyol preferably has a number average molecular weight of 1000 to 3000. If the number average molecular weight is less than 1000, the rubber layer may not exhibit satisfactory rubber elasticity and may have high rigidity. On the other hand, if the number average molecular weight exceeds 3000, the rubber layer may not be provided with satisfactory rubber strength, and the rubber layer may be too flexible.
The number average molecular weight is a measured value in terms of polystyrene by GPC (gel permeation chromatograph) measurement.

The cross-linking agents are 1,4-butanediol (1,4-BD) and 1,4-bis (β-hydroxyethoxy) benzene (BHEB).
By using 1,4-BD and BHEB in combination as a crosslinking agent, the wear resistance of the rubber layer can be improved.
Furthermore, when the crosslinking agent is 1,4-BD and BHEB, the rubber layer can easily exhibit appropriate rubber hardness and rubber rigidity. In addition, a thermosetting urethane composition containing 1,4-BD and BHEB as a crosslinking agent has a relatively long pot life and can be molded by hand casting.

The thermosetting urethane composition preferably further contains silicone oil.
A rubber layer made of a cured product of a thermosetting urethane composition containing silicone oil has a long life due to a low friction coefficient. Moreover, when the said rubber layer is provided, the sound (operating sound) at the time of hulling becomes small. Further, when the rubber layer is provided, the surface of the hulling roll (the surface of the rubber layer) is wrapped with the silicone oil by the bleeding of the silicone oil, so that the water resistance (including during storage) is improved. It will be.
The silicone oil is not particularly limited, and for example, polydimethylsiloxane and modified products thereof can be used.
The viscosity of the silicone oil is preferably 20 to 1000 mPa · s (cps).
When the viscosity of the silicone oil is less than 20 mPa · s, the amount of bleed of the silicone oil may be excessive. On the other hand, when it exceeds 1000 mPa · s, dispersibility may be lowered or bleeding may not occur.

In the thermosetting urethane composition, the content of the silicone oil is preferably 0.3 to 5% by weight, preferably 0.5 to 3%, based on the total amount of the isocyanate component, the polyol component and the crosslinking agent. Weight percent is more preferred.
When the content of the silicone oil is less than 0.3% by weight, the effect of blending the silicone oil may not be sufficiently obtained. On the other hand, if it exceeds 5% by weight, the surface of the rubber layer may become sticky, and the hardness and physical properties of the rubber layer may decrease.

The thermosetting urethane composition further includes chain extenders, reaction aids such as crosslinking accelerators and crosslinking retarders, hydrolysis inhibitors, reinforcing materials such as inorganic fibers and inorganic fillers, colorants, light stabilizers, Various additives such as a heat stabilizer, an antioxidant, an antifungal agent, a flame retardant, and a filler (a bulking agent) may be contained as necessary.

The rubber layer (cured product of the thermosetting urethane composition) preferably has a JIS-A hardness at 20 ° C. of 85 ° or more. When the JIS-A hardness is less than 85 °, the rubber layer is too soft and wear resistance may be reduced.
The JIS-A hardness is more preferably 88 ° or more, and still more preferably 90 ° or more.
On the other hand, the JIS-A hardness at 20 ° C. of the rubber layer is preferably less than 99 °. If it exceeds 99 °, the rice may be damaged at the time of scouring, and the occurrence rate of so-called broken rice may increase.
The JIS-A hardness of the rubber layer is preferably about 88 to 92 ° when the rice to be crushed is relatively soft japonica rice or the like. Further, when the rice to be crushed is relatively hard indica rice or the like, it is preferably about 92 to 96 °.
The JIS-A hardness may be measured according to JIS K 6253 (however, the measurement temperature is 20 ° C.).
The “rubber layer” in the present invention corresponds to the “rubber part” referred to in JIS B 9124.

The rubber layer (cured product of the thermosetting urethane composition) preferably has a tan δ peak temperature (Tg) of 10 ° C. or lower. This is because appropriate rubber elasticity is exhibited at a temperature of 30 to 50 ° C., which is the temperature of the rubber layer during use.

The rubber layer (cured product of the thermosetting urethane composition) preferably has a DIN wear loss of 60 to 100 mm ³ .
If the DIN wear loss is less than 60 mm ³ , the rate of crushed rice may be high during rice milling. On the other hand, the DIN abrasion loss is more than 100 mm ^3, the insufficient durability of the rubber layer.
The DIN wear loss may be measured according to the DIN wear test of JIS K 6264.

The thickness of the rubber layer is not particularly limited, and may be set as appropriate according to the specifications of the hulling machine to which the hulling roll is attached and the JIS standard (JIS B 9214), as in the conventional product.
The thickness of the rubber layer (indicated by T in FIG. 1B) refers to a value that is ½ of the difference between the outer diameter and the inner diameter of the rubber layer when not in use.

In the hulling roll of the present invention, a primer layer and / or an adhesive layer is formed between them in order to further improve the adhesion between the shin material part and the rubber layer, or on the outer peripheral surface of the shin material part. A surface treatment for improving the adhesion to the rubber layer may be applied.
The adhesive can be formed using, for example, a phenol-based adhesive or the like.
The primer layer can be formed using, for example, a urethane-based, polyester-based, silane-based, polyamide-based, or phenol-based primer, a silane coupling agent, or the like.
Examples of the surface treatment include formation of a roughened surface. The roughened surface may be formed by, for example, blasting, grinding, etching, plating, polishing, oxidation, or the like.

The hulling roll preferably has a roundness of a cross section (cross section perpendicular to the rotation axis in use) of 0.5 mm or less. When the roundness exceeds 0.5 mm, the variation in the spacing between the hulling rolls during use increases, and the removal rate may decrease or the occurrence rate of broken rice may increase.

Next, the manufacturing method of the hulling roll of this invention is demonstrated.
The hulling roll can be manufactured, for example, through the following steps (1) and (2).
(1) First, a shin material part is prepared. The above-mentioned shin material part can be produced by a conventionally known method, for example, it can be produced by aluminum die casting or the like.
Thereafter, if necessary, an adhesive layer and / or a primer layer are formed on the outer peripheral surface of the shin material part, or a surface treatment is applied to the outer peripheral surface of the shin material part.

(2) Next, a rubber layer is formed around the shin material part. Here, after placing the shin material part in a cylindrical mold, the above-described thermosetting urethane composition is injected into the gap between the outer peripheral surface of the shin material part and the inner wall surface of the mold. Thereafter, the rubber layer is formed by curing the thermosetting urethane composition under predetermined conditions.
At this time, the curing conditions of the thermosetting urethane composition are not particularly limited, and may be appropriately set in the thermosetting urethane composition according to the composition. As the curing conditions, it is usually possible to employ conditions of heating at 100 to 160 ° C. for 30 to 90 minutes.
Further, after performing the curing treatment under the above conditions and removing the cured product from the mold, for example, post-curing may be performed at 100 to 160 ° C. for 3 to 48 hours.

By using such a method, by laminating a rubber layer on the outer peripheral surface of the shin material part, it is possible to produce a hulling roll in which a rubber layer having a uniform density throughout is formed.
This is because the thermosetting urethane composition used in the present invention has a relatively slow curing after preparation.
In the method for manufacturing the hulling roll, the surface of the rubber layer may be formed by grinding as necessary. Of course, it is not necessary to perform the grinding process while removing the mold from the mold.

Next, the usage method of the hulling roll of this invention is demonstrated.
FIG. 2 is a schematic diagram for explaining a method of using the hulling roll of the present invention.
The hulling roll of the present invention is used by attaching two hulling rolls as one set to a conventionally known rubber roll type hulling machine.
That is, as shown in FIG. 2, a pair of hulling rolls 10A and 10B are mounted in parallel so as to have a predetermined interval L, and each of hulling rolls 10A and 10B is opposite to each other at different rotational speeds (hulling rolls). Rotate at a rotational speed Va of 10A ≠ rotational speed Vb of the hulling roll 10B. In this state, when the rice bran 1 is introduced between the rice bran rolls 10A and 10B, the rice husk is removed from the rice bran rice 1 due to the difference in peripheral speed between the rice hulling roll 10A and the rice bran roll 10B.

The distance L between the hulling roll 10A and the hulling roll 10B and the rotational speeds (peripheral speeds) Va and Vb of the hulling roll 10A and the hulling roll 10B when using the hulling roll are not particularly limited. May be set as appropriate according to various conditions such as the specifications, the type and the drying rate of dried rice, the processing rate, and the putting rate.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

1. Preparation of thermosetting urethane composition (Preparation Example 1)
100 parts by weight of urethane prepolymer (Samprene P6814, manufactured by Sanyo Chemical Co., Ltd.) having MDI as an isocyanate component and polyethylene adipate ester diol (PEA) as a polyol component, silicone oil (manufactured by Toray Dow Corning, SH-200 (100 mPa · s)) 1.0 part by weight, 0.02 part by weight of yellow pigment (ZA Yellow # 200, manufactured by Mikuni Chemical Co., Ltd.) and 0.02 part by weight of white pigment (ZA White # 2200, manufactured by Mikuni Chemical Co., Ltd.) Were mixed with an agitator. Next, 1.59 parts by weight of 1,4-butanediol (manufactured by BASF Japan) and 10.50 parts by weight of BHEB (manufactured by Mitsui Chemicals) are additionally mixed with the obtained mixture to obtain a thermosetting urethane composition. A was prepared.

(Preparation Example 2)
100 parts by weight of urethane prepolymer (Samprene P6814, manufactured by Sanyo Chemical Co., Ltd.), 0.02 parts by weight of yellow pigment (ZA Yellow # 200), and 0.02 parts by weight of white pigment (ZA White # 2200) are mixed in an agitator. did. Next, 1.59 parts by weight of 1,4-butanediol (manufactured by BASF Japan) and 10.50 parts by weight of BHEB (manufactured by Mitsui Chemicals) are additionally mixed with the obtained mixture to obtain a thermosetting urethane composition. B was prepared.

(Preparation Example 3)
A thermosetting urethane composition C was prepared in the same manner as in Preparation Example 2, except that the amount of 1,4-butanediol mixed was 6.56 parts by weight, and BHEB was not mixed.

(Preparation Example 4)
A thermosetting urethane composition D was prepared in the same manner as in Preparation Example 2, except that 1,4-butanediol was not mixed and the amount of BHEB was 14.37 parts by weight.

(Preparation Example 5)
A thermosetting urethane composition E was prepared in the same manner as in Preparation Example 1, except that the amount of 1,4-butanediol mixed was 6.56 parts by weight and BHEB was not mixed.

(Preparation Example 6)
Polyethylene adipate ester diol (PEA) (Vulcolan 2000MM, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 100 parts by weight, NDI (Desmodule 15, manufactured by Sumitomo Bayer Urethane Co., Ltd.) 25 parts by weight, Silicone oil (SH-200 (100 mPa · s)) 1 0.0 part by weight, 0.02 part by weight of yellow pigment (ZA Yellow # 200) and 0.02 part by weight of white pigment (ZA White # 2200) were mixed with an agitator. Next, 5.0 parts by weight of 1,4-butanediol (manufactured by BASF Japan) was additionally mixed with the obtained mixture to prepare a thermosetting urethane composition F.

2. Production and evaluation of hulling roll (1)
Example 1
In this example, a hulling roll having a model size of 60 was produced.
First, the shin material part having the shape shown in FIG. 1 was cast by aluminum die casting.
Next, the above-mentioned shin material part was installed in a cylindrical mold so that the distance between the outer peripheral surface of the above-mentioned sinter material part and the inner peripheral surface of the above-mentioned mold was almost equal.
Thereafter, the thermosetting urethane composition A is injected into the gap between the outer peripheral surface of the above-mentioned shin material part and the inner peripheral surface of the above-mentioned mold, and cured under the following conditions, and the outer diameter and width are adjusted by cutting. And the hulling roll by which the rubber layer was laminated | stacked on the outer peripheral surface of the said shin material part was produced.

(Curing conditions)
The temperature of the thermosetting urethane composition A at the time of pouring was set to 105 ° C. and cured at a mold temperature of 130 ° C. for 60 minutes.
Thereafter, the mold was removed from the mold, and post-curing was performed at 110 ° C. for 24 hours.

(Example 2)
A hulling roll was produced in the same manner as in Example 1 except that the thermosetting urethane composition B was used in place of the thermosetting urethane composition A.

(Comparative Example 1)
A hulling roll was produced in the same manner as in Example 1 except that the thermosetting urethane composition C was used in place of the thermosetting urethane composition A.

(Comparative Example 2)
A hulling roll was produced in the same manner as in Example 1 except that the thermosetting urethane composition D was used in place of the thermosetting urethane composition A.

(Comparative Example 3)
A hulling roll was produced in the same manner as in Example 1 except that the thermosetting urethane composition E was used in place of the thermosetting urethane composition A.

(Comparative Example 4)
A hulling roll was produced in the same manner as in Example 1 except that the thermosetting urethane composition F was used in place of the thermosetting urethane composition A and the composition was cured under the following conditions.
(Curing conditions)
The temperature of the thermosetting urethane composition F at the time of pouring was set to 125 ° C. and cured at a mold temperature of 130 ° C. for 60 minutes.
Thereafter, the mold was removed from the mold, and post-curing was performed at 110 ° C. for 24 hours.

(Comparative Example 5)
A hulling roll (white roll, integrated large type 60) manufactured by Bando Chemical Co., Ltd. was used as a hulling roll of this comparative example. In addition, the said white roll is a hulling roll provided with the rubber layer which has SBR as a main component.

(Comparative Example 6)
A hulling roll manufactured by Bando Chemical Co., Ltd. (red roll, integrated large type 60) was used as a hulling roll of this comparative example. In addition, the said red roll is a hulling roll provided with the rubber layer which has SBR as a main component.

(Evaluation)
(1) Relationship between size and temperature of hulling rolls For hulling rolls of Examples and Comparative Examples, after being allowed to stand at 20 ° C., 45 ° C., and 70 ° C. for 2 hours, the thickness of one side of each hulling roll was measured. .
Here, the standing at 45 ° C. and 70 ° C. for 2 hours was performed by storing in an oven set at each temperature for 2 hours.
In the measurement of the thickness on one side, a 20 cm digital caliper was used to measure three dimensions from the inner surface of the shin material part to the surface of the rubber layer, and the average value was defined as the thickness on one side.
Further, in each hulling roll, the one-side thickness measured at 20 ° C. was set to “100”, and the ratio of the one-side thickness at 45 ° C. and 70 ° C. to the one-side thickness at 20 ° C. was calculated. The results are shown in Table 1.

(2) JIS-A Hardness The JIS-A hardness of the rubber layer formed on the hulling rolls of Examples and Comparative Examples was measured according to JIS K 6253. However, the measurement temperature was 20 ° C., and the measurement locations were three locations. The results are shown in Table 1.

(3) DIN wear reduction The DIN wear reduction of the rubber layer formed on the hulling rolls of Examples and Comparative Examples was evaluated.
For the evaluation of the DIN wear loss, a test piece (diameter 16 mm × thickness 6 mm) having the same composition as that of the rubber layer was separately prepared, and the test piece was used in a method in accordance with JIS K 6264. Rotation: None (Method A), test piece applied force: 10 N. The results are shown in Table 1.

(4) tan δ peak temperature (Tg)
The peak temperature (Tg) of tan δ of the rubber layers formed on the hulling rolls of Examples 1 and 2 and Comparative Examples 4 to 6 was evaluated.
The tan δ peak temperature was evaluated by separately preparing a test piece (width 3 mm × length 40 mm × thickness 1 mm) having the same composition as that of the rubber layer, and using Leopectra-DVE-V4 (manufactured by Rheology Co., Ltd.). Static strain 5%, 10 Hz sine wave tensile excitation was measured in the temperature range 60-100 ° C. The temperature at which the loss coefficient tan δ showed the maximum value was taken as the tan δ peak temperature.

(5) Color tone change (presence of discoloration)
The color tone change of the rubber layer formed on the hulling rolls of Examples and Comparative Examples was evaluated.
For the evaluation of the color tone change, a test piece (size: length 200 mm × width 70 mm × thickness 2 mm) having the same composition as that of the rubber layer was separately prepared, and a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd., Sunshine Weather). Using the meter S80), the test piece was exposed for 120 hours under the conditions specified in the accelerated weathering test of JIS K 6732, and then the change in color tone was observed. The results are shown in Table 1.

As shown in Table 1, the hulling roll of the present invention provided with a rubber layer made of a cured product of a specific thermosetting urethane composition hardly expands during use, and has already been established in the market for reliability. It has the same dimensional stability as the product.
It has also been clarified that the wear resistance of the rubber layer is improved by using 1,4-BD and BHEB in combination as a crosslinking agent.
Moreover, it became clear that the hulling roll of this invention does not discolor at the time of storage.

3. Production and evaluation of hulling roll (2)
Example 3
In this example, a hulling roll having a size of 100 was produced.
Here, the hulling roll was produced using the method similar to Example 1 except having changed the shape and the dimension.

Example 4
A hulling roll was produced in the same manner as in Example 3 except that the thermosetting urethane composition B was used in place of the thermosetting urethane composition A.

(Comparative Example 7)
A hulling roll was produced in the same manner as in Example 3 except that the thermosetting urethane composition C was used in place of the thermosetting urethane composition A.

(Comparative Example 8)
A hulling roll (white roll, integrated large 100 type) manufactured by Bando Chemical Co. was used as a hulling roll of this comparative example.

(Evaluation)
(6) Performance evaluation of hulling roll The relationship between the hulling amount and the wear amount of the rubber layer was evaluated at three facilities described later.
In addition, Toyooka Country Elevator conducted an interview survey on past performance related to the service life of commercial hulling rolls.
(6-1) Evaluation of hulling rolls produced in Examples 3 and 4 Evaluation was performed by Tajima Agricultural Cooperative and Toyooka Country Elevator.
As the huller, a model manufactured by Satake, HA10NC (introduced in 2004) was used.
Sticky rice was brand: glutinous, moisture content (brown rice standard) 14.3 to 14.8%, input rice bran temperature 5 to 15 ° C.
The processing speed was about 4.6 tons / hour.
The removal rate when using the hulling roll of Example 3 was 78%, and the removal rate when using the hulling roll of Example 4 was 79%.

In this evaluation, about 300 tons of polished rice was processed, and the amount of abrasion of the rubber layer of the hulling roll at that time was measured. At this time, the amount of wear is determined by pressing a ruler against each end face of the pair of hulling rolls (main roll and sub roll), measuring the thickness of the remaining rubber layer, and the initial rubber layer thickness (25 mm). Calculated as the difference. The results are shown in Table 2.
In Table 2, the amount of wear before the main roll and before the sub-roll refers to the amount of wear measured at the end surface located in front when the hulling roll is attached to the hulling machine, and after the main roll and after the sub-roll. The amount of wear refers to the amount of wear measured at the end face located on the back side when the hulling roll is attached to the hulling machine.

Further, based on the measurement result of the amount of wear, the expected limit hulling amount (expected value of the weight of kneaded rice that can be hulled) when the hulling roll is used up to its service life (until the thickness of the rubber layer becomes 5 mm). Calculated. The results are shown in Table 2.
The expected limit hulling amount is calculated by calculating the average value (average wear amount) of the four wear amounts measured by the above-described method, and calculating the average wear amount (A) and the weight of the actually processed rice (B ) Based on the following calculation formula (1).
Expected limit hulling amount = weight of rice (B) ÷ [average wear amount (A) / 20] (1)

In addition, as a result of the interview survey at Toyooka Country Elevator, it became clear that the life (limit hulling amount) of the hulling roll (white roll, integrated large type 100) manufactured by Bando Chemical Co., Ltd. is approximately 300 to 400 tons. .

(6-2) Evaluation of the hulling roll produced in Comparative Example 7 The evaluation was performed by Tajima Agricultural Cooperative and Izushi Country Elevator.
As the hulling machine, Satake Co., Ltd., model: HPS100HEA (introduced in 1999) was used. In addition, the sticky rice was brand: Hinohikari, moisture content (brown rice standard) 14.5-16.3%, input rice bran temperature 15-28 ° C.
The processing speed was about 2.5 tons / hour.
The removal rate in Comparative Example 7 was 79%.

In this evaluation, about 220 tons of polished rice was processed, and the amount of wear of the rubber layer of the hulling roll at that time was measured. The results are shown in Table 2.
Further, the expected limit hulling amount was calculated based on the measurement result of the wear amount. The calculation results are shown in Table 2.
Note that the method for measuring the wear amount and the method for calculating the expected limit hulling amount are the same as in (6-1) above.

(6-3) Evaluation of the hulling roll produced in Comparative Example 8 The evaluation was performed by the Hyogo Minami Agricultural Cooperative and Inami Country Elevator.
As the hulling machine, a model made by Satake, HPS100HEA (introduced in 1999) was used.
Sticky rice was made into brands: Hinohikari and Kinuhikari, moisture content (brown rice standard): 14.3% (Hinohikari), 14.1% (Kinuhikari).
The processing speed was about 2.0 tons / hour.
In addition, the removal rate at the time of using the hulling roll of the comparative example 8 was comparable as the case where the conventional hulling roll was used.

In this evaluation, about 350 tons of polished rice was processed, and the amount of abrasion of the rubber layer of the hulling roll at that time was measured. The results are shown in Table 2.
Further, the expected limit hulling amount was calculated based on the measurement result of the wear amount. The calculation results are shown in Table 2.
Note that the method for measuring the wear amount and the method for calculating the expected limit hulling amount are the same as in (6-1) above. However, in Comparative Example 8, the amount of wear was measured only at two locations before the main roll and before the sub roll.

As shown in Table 2, the hulling roll of the present invention having a rubber layer made of a cured product of a specific thermosetting urethane composition is excellent in durability, and can be used for a long time. The frequency of roll replacement can be reduced.
Moreover, it became clear that when the said thermosetting urethane composition contains a silicone oil, durability improves.

10, 10A, 10B Hulling roll 11 Sinter material part 11a Mounting flange 12 Rubber layer

Claims

A hulling roll comprising a shin part and a rubber layer laminated on the outer peripheral surface of the shin part,
The rubber layer is composed of a cured product of a thermosetting urethane composition containing a polyol component, an isocyanate component, and a crosslinking agent,
The polyol component is a polyester polyol,
The isocyanate component is TDI and / or MDI;
A hulling roll characterized in that the cross-linking agent is 1,4-butanediol and 1,4-bis (β-hydroxyethoxy) benzene.
The hulling roll according to claim 1, wherein the isocyanate component is MDI.
The hulling roll according to claim 1 or 2, wherein the rubber layer has a JIS-A hardness at 20 ° C of 85 ° to less than 99 °.
The hulling roll according to any one of claims 1 to 3, wherein the rubber layer has a DIN wear loss of 60 to 100 mm 3 .