JP5879027B2 - Lignin-added thermosetting resin - Google Patents

Description

  The present invention relates to a thermosetting resin to which lignin useful as a biomass thermosetting resin is added.

  In recent years, effective use of plant-derived materials is expected from the viewpoint of environmental conservation. Among plant-derived materials, lignin, which is a major component of wood, together with cellulose, hemicellulose, etc., has not had a useful use so far due to the difficulty of decomposition by microorganisms and the like. It is attracting attention as an additive for thermosetting resins.

  For example, Patent Document 1 describes a resin composition containing a thermoplastic resin and a heat-flowable phenolized lignin. Patent Document 2 describes a method for producing a lignin-modified novolak-type phenol resin obtained by reacting lignin, phenol or a derivative thereof, and aldehydes in the presence of an organic acid.

  However, when lignin is simply added to various resins, the thermal fluidity and reactivity of lignin are low, so that denaturation by lignin does not proceed sufficiently. As a result, the resulting lignin-modified resin molding material has poor moldability, and the resulting molded product also has the problem of poor mechanical strength.

  For this reason, as a general method of using lignin, it has been mainly used to make lignin low-molecular and meltable or solubilized in a solvent. However, low molecular weight of lignin is difficult to put into practical use because it requires large-scale equipment and a large cost.

  On the other hand, thermosetting resins, which are one of plastic materials, have been used in a wide range of fields such as various electric fields and automobile fields. However, such as mechanical strength, heat resistance, and electrical insulation of molded products There is a need for further improvements.

JP 2010-163481 A JP 2008-156601 A

The main subject of this invention is using a lignin as it is, without providing a low molecular weight, and providing a biomass thermosetting resin.
Another object of the present invention is to provide a thermosetting resin having improved properties such as mechanical strength, heat resistance and electrical insulation.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that thermosetting resin molded products obtained by adding herbaceous lignin to thermosetting resins, among other lignins, have mechanical strength and heat resistance. The inventors have found that various properties such as property and electrical insulation are improved, and have completed the present invention.

That is, the lignin-added thermosetting resin of the present invention is characterized by containing a thermosetting resin and a herbaceous lignin.
The present invention also provides a lignin-added thermosetting resin molded product prepared from a molding material prepared from the lignin-added thermosetting resin and molded into a predetermined shape using the molding material.

  The lignin-added thermosetting resin of the present invention has improved properties such as mechanical strength, heat resistance, electrical insulation, and the like, compared with ordinary thermosetting resins, and has been almost discarded until now. Because it is a biomass thermosetting resin that is used effectively, it has the effect of being useful for environmental conservation. In addition, since lignin can be used as it is without reducing its molecular weight, lignin can be used at low cost.

  Hereinafter, the lignin-added thermosetting resin of the present invention will be described in detail. The thermosetting resin of the present invention contains a phenol resin and a herbaceous lignin as main components.

  The thermosetting resin in the present invention is not particularly limited. For example, a novolac phenol resin or a resol phenol resin can be used alone or in combination as a phenol resin. In addition, other general thermosetting resins such as an epoxy resin, a melamine resin, a urea resin, and an unsaturated polyester resin can also be used.

  In the present invention, herbaceous lignin is particularly used as lignin. Lignin is generally classified into woody lignin derived from wood and herbaceous lignin derived from rice straw or wheat straw, and is contained in a waste liquid called black liquor when producing paper from pulp.

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In the present invention, herbaceous lignin extracted from black liquor discharged from the pulp production process by the soda method using rice straw or wheat straw as a raw material is used as a raw material. Herbaceous lignin differs greatly in basic skeleton from woody lignin. That is, the basic skeleton of lignin in the waste liquid is mainly composed of G type, S type, and H type as shown in the following formula. In the formula, an arrow (→) indicates a highly reactive carbon atom.
G type:

S type:

Type H:

  The woody lignin obtained from coniferous pulp waste liquor has a G-type basic skeleton. Woody lignin obtained from hardwood pulp waste liquid has G-type and S-type basic skeletons.

In contrast, herbaceous lignin has G-type, S-type, and H-type basic skeletons, and the basic skeleton differs greatly from wood-based lignin in that it contains H-type.
The feature of this H type is that the G type has one methoxy group and two S types in the ortho position in the phenol basic skeleton, whereas the H type has no methoxy group. . Therefore, herbaceous lignin containing H type has high reactivity because it has less modification of aromatic nuclei than woody lignin containing G type and S type.

  The herbaceous lignin is preferably added in a dry powder form. Drying may be performed before or after powdering. Although drying conditions are not specifically limited, What is necessary is just to dry for about 20 minutes-2 hours at 100-200 degreeC, for example with a drying furnace.

What is necessary is just to grind | pulverize herbaceous lignin to a predetermined particle size, for example with a ball mill etc. The apparatus that can be used in the pulverization process is not particularly limited. For example, in addition to ordinary pulverization apparatuses such as a ball mill, a hammer mill, and a roll mill, a swirling flow jet mill, an opposed jet mill, a wall collision jet mill, and the like A jet mill, an ong mill, a mortar, a multi-stage mortar-type kneading extruder, and the like.
The average particle size of the herbaceous lignin is 0.1 to 1000 μm, preferably 0.1 to 500 μm. When the particle size of the herbaceous lignin exceeds the above range, there is a possibility that a sufficient thermosetting resin modification effect cannot be obtained. On the other hand, if it is below the above range, the particles may aggregate and be unable to be dispersed well in the resin.

Next, in producing the lignin-added thermosetting resin of the present invention, 10 to 300 parts by weight, preferably 20 to 200 parts by weight of herbaceous lignin is added to 100 parts by weight of the thermosetting resin. Is good.
When the amount of herbaceous lignin exceeds the above range, the content of the thermosetting resin is relatively lowered, so that the viscosity of the resulting molding material is increased, and molding is difficult by molding methods such as transfer molding. . On the other hand, if it is below the above range, it may be difficult to improve the properties of the thermosetting resin such as mechanical strength, heat resistance, and electrical insulation.

In addition to the herbaceous lignin, fillers, curing agents, and other additives that are added to ordinary thermosetting resin molding materials can be blended without any particular limitation.
As the filler, for example, wood powder or pulp can be used. Examples of other additives include colorants, plasticizers, stabilizers, mold release agents (metal soaps such as zinc stearate), and the like.
The blending amount of the filler is 10 to 300 parts by mass, preferably 20 to 200 parts by mass with respect to the total amount of the thermosetting resin and the herbaceous lignin.

  In the present invention, a molding material is prepared by blending various additives with the above-described lignin-added thermosetting resin, and a lignin-added thermosetting resin molded product molded into a predetermined shape using the molding material is obtained. . The molding can be performed under the same molding conditions using a molding method similar to that of a normal thermosetting resin such as transfer molding or compression molding. The obtained molded article has improved characteristics such as mechanical strength such as bending strength, heat resistance, and electrical insulation.

これらの配合成分を、混合後、２本ロールにて１００〜１１０℃で５分間混練して、リグニン添加フェノール樹脂成形材料を得た。 EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited by a following example.
[Example 1]
(Novolac phenol resin molding material)
A herbaceous lignin having an average particle size of 60 μm was obtained from the waste liquid produced in the pulp manufacturing process using straw as a raw material.
Using this lignin, each component was mixed in the blending amounts shown in the following table.

After these mixing components were mixed, they were kneaded at 100 to 110 ° C. for 5 minutes with two rolls to obtain a lignin-added phenol resin molding material.

[Comparative Example 1]
A lignin-added phenol resin molding material was obtained in the same manner as in Example 1 except that woody lignin was used instead of the herbaceous lignin. The used woody lignin is obtained by drying lignin recovered from the waste liquid produced in the pulp manufacturing process.

[Comparative Example 2]
A phenol resin molding material was obtained in the same manner as in Example 1 except that herbaceous lignin was not added and each component was mixed in the blending amounts shown in the following table.

[I] Moldability evaluation About the phenol resin molding materials obtained in Example 1 and Comparative Examples 1 and 2, the differential scanning calorimetry (DSC) behavior, the melt viscoelastic behavior, and the thermogravimetric analysis (TG-DTA) behavior were examined. . As a result, no difference was found in the curing characteristics, which was almost the same as the phenol resin molding material (Comparative Example 2) to which lignin was not added.

[II] Evaluation of physical properties of molded products The phenol resin molding materials obtained in Example 1 and Comparative Examples 1 and 2 were molded at 170 ° C for 15 minutes using a transfer molding method to obtain molded products. . The physical properties of the obtained molded product were evaluated. The evaluation method is as follows.
(1) Glass transition temperature (Tg)
Solid dynamic viscoelasticity measurement (frequency: 1 Hz, temperature increase rate: 2 ° C./min) was performed using DMS110 manufactured by SII Nanotechnology. The glass transition temperature (Tg) was the peak temperature of the tan δ curve obtained from the solid dynamic viscoelasticity measurement.
(2) Bending strength According to JIS K6911, the bending strength was measured at a crosshead speed of 3 mm / min and a span of 100 mm.
(3) Deflection temperature under load According to ASTM D648, the temperature when the standard deflection amount (0.25 mm) was reached was measured at a heating rate of 2 ° C./min and a load of 18.5 kg / cm ² .
(4) Coefficient of linear expansion TMA curve obtained by TMA / SS6000 manufactured by SII NanoTechnology Co., Ltd., thermomechanical analysis (TMA) in nitrogen mode, compression mode, heating rate 2 ° C / min. The linear expansion coefficient at 100 ° C. was determined from the slope of.
(5) Volume resistivity (electrical insulation)
According to JIS K6911, volume resistivity (Ω · cm) was measured using HP4339A manufactured by Yokogawa-Hewlett-Packard.
(6) Dielectric constant Using an impedance analyzer E4991A manufactured by Agilent Technologies, the dielectric constant at a frequency of 1 GHz was measured by a capacitance method.
(7) Water absorption The water absorption was determined by measuring the initial weight and the weight increase after being immersed in boiling water for 2 hours, and calculating the water absorption based on the ratio.
These evaluation results are shown in Table 3.

From Table 3, the molded product obtained using the molding material of Example 1 has almost the same heat resistance as the molded product obtained in Comparative Example 1, but the bending strength, electrical insulation and It turns out that it is excellent in water resistance.
On the other hand, when compared with the conventional phenol resin molded product obtained in Comparative Example 2, the molded product obtained in Example 1 has almost the same bending strength and improved heat resistance, electrical insulation and dielectric properties. It can also be seen that the coefficient of linear expansion is small.

{Example 2}
(Resol-based phenolic resin molding material)
Using the same herbaceous lignin used in Example 1, this was mixed with a resole phenolic resin in a 1: 1 weight ratio in methanol, and then the methanol was removed to obtain a lignin-added phenolic resin molding material. It was.
This phenolic resin molding material was molded by compression molding at 200 ° C. for 15 minutes to obtain a molded product. This molded product had high heat resistance. That is, as a result of the solid dynamic viscoelasticity test, the glass transition temperature Tg of the cured product of only resole was 263 ° C., and the Tg of the lignin-added phenol resin cured product was 267 ° C.

Claims (5)

A lignin-added thermosetting resin comprising a thermosetting resin and a herbaceous lignin , wherein the thermosetting resin is a composition of a novolac phenol resin and a curing agent . Containing a thermosetting resin and grassy lignin, thermosetting resin, Les Orres based phenolic resins, melamine resins or lignin added thermosetting resin, which is a urea resin.   The lignin-added thermosetting resin according to claim 1 or 2, wherein the herbaceous lignin is in a dry powder form.   The lignin addition thermosetting resin in any one of Claims 1-3 which added 10-300 weight part of herbaceous lignin with respect to 100 weight part of thermosetting resins.   The lignin addition thermosetting resin molded product which shape | molded the lignin addition thermosetting resin in any one of Claims 1-4 in the predetermined shape.