JP5771088B2 - Solid resol type biomass phenol resin and rubber composition - Google Patents

Description

  The present invention relates to a solid resol type biomass phenol resin and a rubber composition.

In recent years, in order to suppress an increase in the amount of carbon dioxide in the atmosphere, biomass plastics, which are so-called carbon neutral materials using plant-derived raw materials, have attracted attention.
As a biomass plastic, not only a thermoplastic resin but also a thermosetting resin such as a phenol resin has been studied, and a phenol resin obtained by reacting a phenol with a saccharide under an acidic catalyst is disclosed ( For example, see Patent Document 1.)
In addition, a phenol resin for reinforcing rubber obtained by modifying cashew oil, which is a plant-derived alkylphenol, is also disclosed (for example, see Patent Document 2). However, in order to cure these resins, it is necessary to use a curing agent derived from fossil resources such as hexamethylenetetramine.
As a phenol resin that is cured without using a curing agent, a solid resol type phenol resin (for example, see Patent Document 3) and a phenol resin using a polysaccharide as a raw material (for example, see Patent Document 4) are disclosed. Yes.

JP 2010-090297 A JP 2007-269843 A JP 2007-099789 A JP 2008-050543 A

For example, when the phenol resin is blended to improve the properties of the rubber composition, the phenol resin described in Patent Document 1 has a small rubber reinforcing effect and a low plant-derived rate.
In patent document 2, since phenol and formaldehyde are used, there is a problem that the plant-derived rate is low and the reinforcing effect is large but the tensile strength is low.
Moreover, when these phenol resins are blended with rubber, it is necessary to use a curing agent derived from fossil resources such as hexamethylenetetramine.
The solid resol-type biomass phenol resin described in Patent Document 3 can be cured without using a curing agent, but since it is cured in a short time by heat, problems such as thickening during heating and kneading occur. It cannot be kneaded uniformly. Therefore, it is difficult to use in applications that require heating and kneading, such as rubber compounding and molding materials.
An object of the present invention is to provide a solid resol-type biomass phenol resin from which a rubber composition having a high plant-derived rate and a good kneadability capable of giving a vulcanizate excellent in hardness, breaking strength and elongation at break can be obtained. To do. Moreover, it aims at providing the rubber composition from which the vulcanizate excellent in hardness, breaking strength, and elongation at break is obtained.

The present invention has the following configuration.
[1] Obtained by reacting phenols containing plant-derived phenols with aldehydes containing plant-derived aldehydes in the presence of a basic catalyst,
The plant-derived phenols is at least one selected from the group consisting of cashew nut shell liquid (CNSL), cashew oil, cardanol and urushiol,
A solid resol-type biomass phenol resin having a plant-derived rate of 30% by mass or more and a weight average molecular weight of 10,000 or more .
[2] [1] Symbol and solid resol-type biomass phenolic resin of the mounting, the rubber composition characterized by containing a rubber and a filler.

The solid resol-type biomass phenol resin of the present invention has a high plant-derived ratio, is easy to handle because it is solid, and provides a rubber composition with good kneadability that can give a vulcanizate with excellent hardness, breaking strength and breaking elongation. It is done. In addition, the rubber composition of the present invention provides a vulcanizate having excellent hardness, breaking strength and breaking elongation.
In addition, in this specification, a plant-derived rate is a ratio of the plant-derived component of the obtained solid resol type | mold biomass phenol resin. Plant-derived components are obtained by photosynthesis using carbon dioxide in the atmosphere. Therefore, it is considered that the amount of carbon dioxide generated during incineration of plant-derived components is offset by the amount of carbon dioxide absorbed during photosynthesis and does not affect the increase in carbon dioxide in the atmosphere (so-called carbon neutral). Therefore, the higher the plant-derived rate, the more the increase in carbon dioxide in the atmosphere can be suppressed, and the effect of preventing global warming is enhanced. The weight average molecular weight is a numerical value calculated from a calibration curve using a polystyrene standard substance, measured by gel permeation chromatography (GPC) using a solution obtained by dissolving the obtained resol-type biomass phenol resin in tetrahydrofuran as a measurement sample. .

<Solid resol type biomass phenol resin>
The solid resol-type biomass phenol resin of the present invention is characterized by having a plant-derived rate of 30% by mass or more and a weight average molecular weight of 10,000 or more. The solid resol-type biomass phenol resin of the present invention refers to a solid resol-type phenol resin obtained using a plant-derived raw material. That is, it represents a solid phenol resin obtained by reacting phenols and aldehydes in the presence of a basic catalyst, and one or both of the phenols and aldehydes contain plant-derived materials. In addition to the plant-derived materials, non-plant-derived materials such as those derived from fossil resources may be included as raw materials, but the plant-derived materials so that the plant-derived ratio of the obtained solid resol-type biomass phenol resin is 30% by mass or more. The amount used must be adjusted accordingly.
If a plant origin rate is 30 mass% or more, the increase in carbon dioxide emission can be suppressed from the concept of carbon neutral.

Examples of phenols include plant-derived phenols, non-plant-derived phenols, and mixtures thereof.
Plant-derived phenols include cashew nut shell liquid (CNSL), cashew oil, cardanol, urushiol, catechol derived from glucose fermented product, hydroquinone, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type. Among these, cardanol is preferable because it has few impurities and is easily available.
Non-plant-derived phenols include fossil resource-derived phenols, and examples include phenol, resorcin, cresol, xylenol, propylphenol, butylphenol, octylphenol, phenylphenol, bisphenol A, and bisphenol F. These may be used individually by 1 type and may be used in combination of 2 or more type.
When the aldehyde contains a plant-derived raw material, as the phenol, only a plant-derived phenol may be used, or only a non-plant-derived phenol may be used, or a mixture thereof may be used.
When aldehydes do not contain plant-derived raw materials, plant-derived phenols or a mixture of plant-derived phenols and non-plant-derived phenols is used as phenols.
It is preferable that 10 mass% or more of plant-derived phenols are contained as the whole phenols, and it is more preferable that it is 20 mass% or more. If it is 10 mass% or more, since a high plant-derived rate can be hold | maintained, it is preferable.

Examples of aldehydes include plant-derived aldehydes, non-plant-derived aldehydes, and mixtures thereof.
Examples of plant-derived aldehydes include furfurals, and examples thereof include furfural, 5-methylfurfural, and hydroxymethylfurfural. These may be used individually by 1 type and may be used in combination of 2 or more type.
Non-plant derived aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde, salicylaldehyde and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.
When phenols contain plant-derived raw materials, as plant aldehydes, only plant-derived aldehydes, non-plant-derived aldehydes may be used, or a mixture thereof may be used.
When phenols do not contain plant-derived raw materials, plant-derived aldehydes or a mixture of plant-derived aldehydes and non-plant-derived aldehydes is used as aldehydes.
It is preferable that 30 mass% or more of plant-derived aldehydes are contained as the whole aldehyde, and it is more preferable that it is 50 mass% or more. 30% by mass or more is preferable because a high plant-derived rate can be maintained.

  The mass ratio of phenols and aldehydes in obtaining a solid resol-type biomass resin is preferably 1 to 20 times, preferably 1.5 to 6 times, when the aldehydes are taken as 1. It is more preferable. If the phenols are 1 or more times, gelation can be suppressed, and if they are 20 or less, the reaction rate can be increased to increase the molecular weight.

A basic catalyst is used in the reaction between phenols and aldehydes. Basic catalysts include alkali metal or alkaline earth metal hydroxides (eg, sodium hydroxide, calcium hydroxide, barium hydroxide, lithium hydroxide), amines (eg, ammonium hydroxide, diethylamine, triethylamine). , Triethanolamine, ethylenediamine, hexamethylenetetramine, etc.). These may be used individually by 1 type, or may be used in combination of 2 or more type.
The amount of the basic catalyst used is preferably 0.1 to 50% by mass and more preferably 0.5 to 5% by mass with respect to the total mass of the phenols and aldehydes. If the usage-amount of a basic catalyst is 0.1 mass% or more, reaction can fully be advanced, and if it is 50 mass% or less, gelatinization can be suppressed.

  The reaction temperature is preferably 20 to 200 ° C, more preferably 120 to 160 ° C. If reaction temperature is 20 degreeC or more, reaction can fully advance, and if it is 200 degrees C or less, thermal decomposition can be suppressed.

  The reaction time is preferably 0.5 to 20 hours, and more preferably 2 to 10 hours. If the reaction time is 0.5 hours or longer, the reaction can be sufficiently progressed, and if it is 20 hours or shorter, a decrease in productivity can be suppressed.

Since the resol-type biomass phenol resin of the present invention has a weight average molecular weight of 10,000 or more, the obtained resol-type biomass phenol resin is solid and easy to handle.
Since the solid resol-type biomass phenol resin obtained in the present invention is self-hardening, it becomes possible to reduce or eliminate the curing agent when blended as a rubber composition. However, a rubber composition having excellent hardness, breaking strength and breaking elongation can be obtained. Moreover, since the gel time is long, it is easy to knead with rubber.
The solid resol-type biomass phenol resin can be used for rubber compounding agents, casting molds, molded products such as automobile parts and electric parts, epoxy curing agents, adhesives, paints, and grinding wheel resins.

<Rubber composition>
The rubber composition of this invention contains the said solid resol type biomass phenol resin, rubber | gum, and a filler.

<Rubber>
The rubber used in the rubber composition of the present invention is not particularly limited, but besides natural rubber (NB), butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), styrene-butadiene rubber (SBR), Synthetic diene rubbers such as acrylonitrile-butadiene rubber (NBR) may be used, and these may be used alone or in combination of two or more. Among these, it is preferable to use natural rubber in order to improve the plant-derived rate in the rubber composition and enhance environmental harmony.
The blending ratio of the rubber and the solid resol type biomass phenol resin used in the rubber composition of the present invention is not particularly limited, but the solid resol type biomass and the phenol resin are 1 to 50 parts by mass, more preferably 1 to 100 parts by mass of the rubber. 30 parts by mass. If phenol resin is more than a lower limit with respect to 100 mass parts of rubber | gum, sufficient hardness can be provided to rubber | gum, and if it is below an upper limit, high breaking elongation can be expressed.

<Filler>
The filler used in the rubber composition of the present invention is not particularly limited, but carbon black, silica, calcium carbonate, magnesium carbonate, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, talc, clay, mica, wood powder, etc. Among them, carbon black and silica are preferable from the viewpoint of imparting hardness to the vulcanizate.
Although the compounding ratio of the filler used for a rubber composition is not specifically limited, It is preferable that it is 10-200 mass parts with respect to 100 mass parts of rubber | gum, and it is more preferable that it is 50-100 mass parts. If the filler content is at least the lower limit value, the mechanical properties of the vulcanizate can be increased, and if it is at most the upper limit value, the fluidity can be increased.

<Curing agent>
The rubber composition of the present invention may use a curing agent. The curing agent cures the solid resol type biomass phenol resin.
The curing agent is not particularly limited, but examples include hexamethylenetetramine, hexamethoxymethylmelamine, paraformaldehyde, glyoxal, etc. Among them, hexamethylenetetramine is economical, compatible with rubber, after rubber composition production It is preferable from the viewpoint of stability.
It is preferable that the compounding quantity of a hardening | curing agent is 30 mass parts or less with respect to 100 mass parts of resol type biomass phenol resin, and it is more preferable that it is 20 mass parts or less. If the blending amount of the curing agent is not more than the upper limit value, the gas generated during rubber kneading can be suppressed, and the vulcanizate can have sufficient hardness.

<Other additives>
The rubber composition may contain additives such as pigments, mold release agents, antioxidants, silane coupling agents, ultraviolet absorbers, curing accelerators, and antioxidants.

<Method for producing rubber composition>
The rubber composition of the present invention is produced by a general method, for example, by kneading the solid resole type biomass phenol resin, rubber, filler, and other additives to be used as necessary with a Banbury mixer, roll, kneader or the like. be able to.

<Effect>
The rubber composition of the present invention can provide a vulcanizate having excellent hardness, breaking strength and breaking elongation.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited at all by these Examples.

(Manufacture of phenolic resin)
[Example 1]
To a flask equipped with a stirrer, a cooler, and a thermometer, 180 g of cardanol, 12 g of a 30 mass% sodium hydroxide aqueous solution and 100 g of furfural were added, and the reaction was carried out at 150 ° C. for 6 hours while removing the water generated during the temperature rise. After diluting by adding 300 g of methyl isobutyl ketone (hereinafter “MIBK”), 10% by mass hydrochloric acid was added to adjust the pH to 5, followed by desalting by washing with water. Thereafter, the temperature was raised to 160 ° C. under a reduced pressure of 11 kPa, and MIBK and water were distilled off to obtain 230 g of a phenol resin (A).

[Example 2]
To a flask equipped with a stirrer, a cooler, and a thermometer, 120 g of cardanol, 385 g of phenol, 29 g of a 30% by mass sodium hydroxide aqueous solution and 144 g of furfural are added, and the water generated during the temperature rise is removed for 6 hours at 150 ° C. Reacted. 10 mass% hydrochloric acid was added so that it might become pH 5, and it heated up to 150 degreeC under pressure reduction of 11 kPa, and 286 g of unreacted phenol was distilled off. After diluting by adding 300 g of MIBK, it was desalted by washing with water. Then, it heated up to 160 degreeC under pressure reduction of 11 kPa, MIBK and water were distilled off, and 291-g phenol resin (B) was obtained.

[Example 3]
To a flask equipped with a stirrer, a cooler, and a thermometer, add 180 g of cardanol, 12 g of 30% by weight aqueous sodium hydroxide, 115 g of furfural, 3.5 g of 92% by weight paraformaldehyde, and remove the water generated during temperature rise. , Reacted at 150 ° C. for 6 hours. After diluting by adding 300 g of MIBK, 10% by mass hydrochloric acid was added to adjust the pH to 5, followed by desalting with water. Thereafter, the temperature was raised to 160 ° C. under a reduced pressure of 11 kPa, and MIBK and water were distilled off to obtain 251 g of a phenol resin (C).

[Example 4]
Water that is produced during heating is added to a flask equipped with a stirrer, a cooler, and a thermometer, and 120 g of cardanol, 456 g of phenol, 29 g of a 30% by mass sodium hydroxide aqueous solution, 144 g of furfural, and 92 g% paraformaldehyde are added. The reaction was carried out at 150 ° C. for 6 hours. 10 mass% hydrochloric acid was added so that it might become pH 5, and it heated up to 150 degreeC under pressure reduction of 11 kPa, and 266 g of unreacted phenol was distilled off. After diluting by adding 300 g of MIBK, it was desalted by washing with water. Thereafter, the temperature was raised to 160 ° C. under a reduced pressure of 11 kPa, and MIBK and water were distilled off to obtain 281 g of a phenol resin (D).

[Comparative Example 1]
To a flask equipped with a stirrer, a cooler, and a thermometer, 180 g of cardanol, 10 g of a 30 mass% sodium hydroxide aqueous solution and 58 g of furfural were added, and the reaction was carried out at 150 ° C. for 6 hours while removing water generated during the temperature rise. After diluting by adding 300 g of MIBK, 10% by mass hydrochloric acid was added to adjust the pH to 5, followed by desalting with water. Then, it heated up to 160 degreeC under pressure reduction of 11 kPa, MIBK and water were distilled off, and 188g phenol resin (E) was obtained.

[Comparative Example 2]
To a flask equipped with a stirrer, a cooler, and a thermometer, 56 g of CNSL and 0.28 g of sulfuric acid were added and reacted at 200 ° C. for 10 hours. The temperature was lowered to 50 ° C., 188 g of phenol, 78 g of 50% by mass formalin, and 0.94 g of sulfuric acid were added and reacted at 100 ° C. for 5 hours. Then, it heated up to 180 degreeC under pressure reduction of 11 kPa, 70 g of unreacted phenol was distilled off, and 210 g of phenol resin (F) was obtained.

[Comparative Example 3]
To a flask equipped with a stirrer, a cooler, and a thermometer, 169 g of phenol, 72 g of isomerized sugar HF55 (solid content: 75% by mass) manufactured by Gunei Chemical Industry, and 1.1 g of sulfuric acid are added, and water generated during temperature rise is added. While removing, the reaction was conducted at 155 ° C. for 1 hour. Thereafter, 0.85 g of calcium hydroxide suspended in a small amount of water was added for neutralization. At 200 ° C. and 11 kPa, 76 g of unreacted phenol was distilled off to obtain 119 g of phenol resin (G).

[Comparative Example 4]
300 g of phenol, 100 g of tapioca starch, and 18.6 g of paratoluenesulfonic acid monohydrate were added to a flask equipped with a stirrer, a cooler, and a thermometer, and refluxed for 3 hours. Thereafter, 7.1 g of a 30% by mass aqueous sodium hydroxide solution was added and stirred for 5 minutes. Further, 500 g of ion-exchanged water, 74 g of 50% by mass formalin, and 45 g of hexamethylenetetramine were added and reacted at 70 ° C. for 6 hours. Thereafter, the temperature was raised to 90 ° C. under a reduced pressure of 11 kPa, and 139 g of unreacted phenol and water were distilled off to obtain 249 g of a phenol resin (H).

[Comparative Example 5]
A solid resol type phenolic resin (PS-1180, manufactured by Gunei Chemical Industry Co., Ltd.) having a plant-derived rate of 0% by mass using phenol and formaldehyde, which are non-plant-derived raw materials, as the raw material was used as the phenol resin (I).

The softening point, gel time, torque generation time, and weight average molecular weight of the phenol resins (A) to (I) obtained in Examples 1 to 4 and Comparative Examples 1 to 5 were measured by the following methods. Moreover, the plant origin rate of the phenol resin (A)-(H) obtained in Examples 1-4 and Comparative Examples 1-4 was computed with the following method. These results are shown in Table 1.
However, for phenol resin (E), the gel time and torque generation time cannot be measured because it is pasty, and for phenol resin (H) and phenol resin (I), the gel time when a curing agent is used because it is a self-hardening resin. Was not measured.

[Softening point]
It measured according to JIS K6910.
[Geltime (with curing agent)]
0.1 g of hexamethylenetetramine was added to 1.0 g of the obtained phenol resin, melted on a hot plate at 180 ° C., and the time until gelling was measured while stirring.
[Gel time (no curing agent)]
1.0 g of the obtained phenol resin was melted on a hot plate at 180 ° C., and the time until gelation was measured while stirring.
[Torque generation time (with curing agent)]
2.8 g of the obtained phenol resin, 0.4 g of hexamethylenetetramine (manufactured by Mitsubishi Gas Chemical Company), and 3.2 g of wood powder (manufactured by Kaneki Fuel Co., Ltd.) were pulverized and mixed to form a tablet having a diameter of about 3 cm. A curast meter (manufactured by CURELASTOMETER JSR) was used for the obtained molded product, and the time until a torque of 60 kgf · cm was generated at 160 ° C. was measured.
[Torque generation time (no curing agent)]
2.8 g of the obtained phenol resin and 3.2 g of wood flour (manufactured by Kaneki Fuel Co., Ltd.) were pulverized and mixed to form a tablet having a diameter of about 3 cm. A curast meter (manufactured by CURELASTOMETERJSR) was used for the obtained molded product, and the time until a torque of 60 kgf · cm was generated at 160 ° C. was measured. The slower this torque generation time, the easier the heat kneading.
[Weight average molecular weight]
The weight average molecular weight was calculated from a calibration curve using a polystyrene standard substance by measuring a gel permeation chromatography (GPC) under the following conditions using a solution obtained by dissolving the obtained resol-type biomass phenol resin in tetrahydrofuran as a measurement sample.
GPC measurement conditions Apparatus: HLC-8120 (manufactured by Tosoh Corporation)
Column: TSK-GEL3000HXL, 2000HXL, 2000HXL (manufactured by Tosoh Corporation)
Detector: UV-8020 (manufactured by Tosoh Corporation)
[Plant-derived rate]
For Examples 1, 2, 3, and 4 Comparative Examples 1, 2, and 4, plant-derived rates were calculated based on Formula (A) and Comparative Example 3 based on Formula (B).
Formula (A): Plant-derived rate [%] = 100 − {[(phenol feed mass) − (distilled unreacted phenol mass) + [(92 mass% paraformaldehyde feed mass) × 0.92 × 0.47 ] + [(50 mass% paraformaldehyde charged mass) × 0.5 × 0.47] + [(hexamethylenetetramine charged mass) × 1.3 × 0.47] + (mass of neutralized salt (theoretical value) )] / (Resin yield mass) × 100}
Here, 0.47 is a coefficient for calculating the amount derived from formaldehyde in the resin skeleton. That is, it is a numerical value obtained by dividing the molecular weight (14) of the formaldehyde-derived crosslinking group (—CH ₂ —) in the resin skeleton by the molecular weight (30) of formaldehyde (HCHO).
1.3 is a coefficient for calculating the amount of formaldehyde produced from hexamethylenetetramine. That is, since 6 mol of formaldehyde is generated from 1 mol of hexamethylenetetramine, the value is obtained by multiplying the molecular weight of formaldehyde (30) by 6 and dividing by the molecular weight of hexamethylenetetramine (140).
Formula (B): Plant-derived rate [%] = [(CNSL preparation mass) / (resin yield mass)] × 100

From the results in Table 1, the phenol resins (A) to (D) obtained in Examples 1 to 4 have a weight average molecular weight of 10,000 or more, are easy to handle in a solid state, and have a high plant-derived rate. Moreover, since the torque generation time was long, kneading was easy, and it was confirmed that the composition could be cured without using a curing agent.
Although the phenol resin (E) obtained in Comparative Example 1 has a high plant-derived ratio, it has a low weight average molecular weight of 3,800, and thus becomes a paste and difficult to handle during kneading, and cannot be used as a rubber composition.
Since the phenol resins (F) and (G) obtained in Comparative Examples 2 and 3 are novolak type phenol resins, they are solid even if the weight average molecular weight is small, but the plant-derived rate is low. Further, when no curing agent is used, it does not cure even after 1 hour.
The phenol resin (H) obtained in Comparative Example 4 has a low plant-derived rate, a short torque generation time, and thus poor kneadability, and a short gel time when no curing agent is used.
Since all the phenol resins (I) obtained in Comparative Example 5 use the non-plant-derived rate as a raw material, the plant-derived rate is zero, and the kneadability is poor because the torque generation time is short, and no curing agent is used. The gel time is short.

(Production of rubber material)
Various compounding materials used in the production of the rubber composition will be described together below.
Natural rubber (NR): RSS No. 3 Carbon black: HAF (Mitsubishi Chemical Corporation)
Oil: Diana Process AH40 (made by Idemitsu Kosan Co., Ltd.)
Anti-aging agent: NOCRACK 6C (manufactured by Ouchi Shinko Chemical Co., Ltd.)
Stearic acid: Sakura stearate (manufactured by NOF Corporation)
Sulfur: Sulfur (manufactured by Tsurumi Chemical Co., Ltd.)
Zinc flower: Zinc oxide (manufactured by Sakai Chemical Co., Ltd.)
Curing agent: Hexamethylenetetramine (Mitsubishi Gas Chemical Co., Ltd.)
Vulcanization accelerator: Noxeller NS-P (Ouchi Shinko Chemical Co., Ltd.)
Curing aid: Calcium hydroxide (Kitakami Lime)

(Production of rubber material using curing agent)
[Example 5]
10 g of phenol resin (A), 100 g of natural rubber, 60 g of carbon black, 2 g of wax, 4 g of oil, 2 g of anti-aging agent, 4 g of stearic acid as a lubricant and 5 g of zinc white were kneaded in a pressure kneader at 140 ° C. for 5 minutes. To this, 2.5 g of sulfur, 5 g of a curing agent, and 1.5 g of a vulcanization accelerator were added and kneaded with a biaxial roll at 100 ° C. for 5 minutes to obtain a sheet-like unvulcanized rubber composition.

[Examples 6 to 8 Comparative Examples 6 and 7]
An unvulcanized rubber composition was obtained in the same manner as in Example 5 except that the phenol resin (A) was changed to the phenol resin shown in Table 2.
However, the phenolic resin (E) could not be kneaded because it was in the form of a paste, and the phenolic resin (H) and the phenolic resin (I) were not hardened because they were self-hardening resins.

(Manufacture of rubber composition without using curing agent)
[Example 9]
10 g of phenol resin (A), 100 g of natural rubber, 60 g of carbon black, 2 g of wax, 4 g of oil, 2 g of anti-aging agent, 4 g of stearic acid as a lubricant and 5 g of zinc white were kneaded in a pressure kneader at 140 ° C. for 5 minutes. To this, 2.5 g of sulfur, 0.5 g of a curing aid and 1.5 g of a vulcanization accelerator were added and kneaded with a biaxial roll at 100 ° C. for 5 minutes to obtain a sheet-like unvulcanized rubber composition.

[Examples 10 to 12, Comparative Examples 8 to 11]
An unvulcanized rubber composition was obtained in the same manner as in Example 9 except that the phenol resin (A) was changed to the phenol resin shown in Table 3.
However, the phenolic resin (E) could not be kneaded because it was pasty, and was not carried out. Moreover, the phenol resin (H) and the phenol resin (I) of Comparative Examples 10 and 11 were cured during kneading and could not be uniformly kneaded, and an unvulcanized rubber composition could not be obtained. .

(Manufacture of vulcanizates)
[Comparative Example 12]
100 g of natural rubber, 60 g of carbon black, 2 g of wax, 4 g of oil, 2 g of anti-aging agent, 4 g of stearic acid and 5 g of zinc white as a lubricant were kneaded in a pressure kneader at 140 ° C. for 5 minutes. To this, 2.5 g of sulfur and 1.5 g of a vulcanization accelerator were added and kneaded with a biaxial roll at 100 ° C. for 5 minutes to obtain a sheet-like unvulcanized rubber composition.

  The test pieces were obtained by press vulcanizing the unvulcanized rubber compositions obtained in Examples 5 to 12 and Comparative Examples 6 to 9 and 12 using a 150 mm × 150 mm × 2 mm mold at 150 ° C. for 30 minutes. Obtained. About the obtained test piece, hardness, breaking strength, and breaking elongation were measured by the following methods. The measurement results of Examples 5 to 8 and Comparative Examples 6 to 7 using a curing agent are shown in Table 2, and the measurement results of Examples 9 to 12 and Comparative Examples 8 to 12 without using a curing agent are shown in Table 3. .

[Hardness]
In accordance with JIS K6253, the hardness (Shore A) was measured using a type A durometer GS-719G manufactured by Teclock. The greater the hardness value, the harder the vulcanizate is obtained and the better the reinforcement.
[Break strength / break elongation]
In accordance with JIS K6251, the breaking strength and breaking elongation of the test piece having a dumbbell shape No. 3 were measured with a strograph V10-C manufactured by Toyo Seiki. The higher the value of breaking strength and breaking elongation, the better the tensile strength.

From the result of Table 2 using a hardening | curing agent, Examples 5-8 are hard compared with Comparative Examples 6-7, and a rubber reinforcement effect is large. Moreover, it turned out that it is excellent also in breaking strength and breaking elongation.
From the results of Table 3 using a curing agent, Examples 9 to 12 can be kneaded without problems, and all of hardness, breaking strength and breaking elongation are improved as compared with Comparative Example 13 containing no phenol resin. Excellent rubber reinforcement effect.
On the other hand, in Comparative Examples 8 and 9, the test piece could not be produced without curing.
Further, in Comparative Examples 10 and 11, curing progressed during kneading, and uniform kneading could not be performed.
Furthermore, since Examples 5-12 use the phenol resin with a high plant-derived rate, the plant-derived rate is increased even in the entire rubber composition, and it is considered that there is an effect of suppressing an increase in the amount of carbon dioxide.

Claims (2)

Obtained by reacting phenols containing plant-derived phenols and aldehydes containing plant-derived aldehydes in the presence of a basic catalyst,
The plant-derived phenols is at least one selected from the group consisting of cashew nut shell liquid (CNSL), cashew oil, cardanol and urushiol,
A solid resol-type biomass phenol resin having a plant-derived origin rate of 30% by mass or more and a weight average molecular weight of 10,000 or more. A rubber composition comprising the solid resol-type biomass phenol resin according to claim 1 , rubber and a filler.