Resin composition for binder

Abstract

To provide a resin composition for a binder containing a biomass-derived raw material, from which a binder having good handleability can be obtained due to excellent compatibility with petroleum-based heavy fuel oil.SOLUTION: A resin composition for a binder contains a lignin-modified novolac type phenol resin, and hydrophobic hydrocarbon.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for binders, and more particularly to a resin composition for use as an asphalt binder or pitch binder, which is a material for road paving, waterproofing, adhesives, carbon materials, or refractories. [Background technology]

[0002] In the road construction and paving industries, asphalt paving is performed by spreading a hot, compacted, hardened asphalt mixture in a uniform layer on the roadbed or an already constructed road, and then compressing the uniform layer by rolling with a heavy roller to form a smooth surface. The asphalt mixture is composed of coarse and fine aggregates (including gravel, stone, and sand) and a heated liquid asphalt binder, which is the cement that holds the aggregates together. The asphalt binder typically contains heavy petroleum oils such as asphaltenes, resins, and solvents.

[0003] Furthermore, for example, in refractories for blast furnaces, clay-like amorphous refractories are used which are produced by kneading silicate raw materials or alumina raw materials, clay-based raw materials, carbonaceous materials, silicon carbide materials or silicon nitride materials with a binder composed of tar, pitch and resin.

[0004] Because the petroleum-based heavy oil and petroleum- or coal-based pitch used in the binders are obtained from fossil resources, attempts have been made to replace some of the components of asphalt binders with biomass-derived components from the perspectives of reducing carbon dioxide emissions and environmental impact (e.g., Patent Document 1). Patent Document 1 describes an asphalt composition containing bitumen, vegetable oil, and a lignin preparation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2021-502461 Summary of the Invention [Problem to be solved by the invention]

[0006] However, lignin used in conventional asphalt binders does not melt on heat, making it impossible to melt-mix it with pitch, asphalt, etc. Also, it is difficult to adjust the softening point. [Means for solving the problem]

[0007] The present invention has been made in view of the above problems, and has been completed based on the finding that lignin-modified novolak phenolic resin has high compatibility with petroleum-based heavy oils and the like, and can be suitably used as an asphalt binder material.

[0008] According to the present invention, there is provided the following resin composition for binders. [1] A resin composition for binders, comprising a lignin-modified novolac-type phenolic resin and a hydrophobic hydrocarbon. [2] The resin composition for binders according to [1], wherein the lignin-modified novolac phenolic resin has a lignin modification rate of 5% or more and 60% or less. [3] The resin composition for binders according to [1] or [2], wherein the softening point of the lignin-modified novolac phenolic resin is 150°C or lower. [4] The binder resin composition according to any one of [1] to [3], wherein the hydrophobic hydrocarbon contains an aromatic ring. [5] The resin composition for binders according to any one of [1] to [4], wherein the hydrophobic hydrocarbon contains a residue or extract of crude oil or coal. [6] The resin composition for binders according to any one of [1] to [5], wherein the hydrophobic hydrocarbon includes asphalt, coal tar, or coal tar pitch. [7] The resin composition for binders according to [6], wherein the asphalt is at least one selected from the group consisting of natural asphalt, petroleum asphalt, petroleum pitch, recycled asphalt, and modified asphalt. [8] The resin composition for binders according to any one of [1] to [7], further comprising a curing agent. [9] The resin composition for binders according to [8], wherein the curing agent contains at least one selected from hexamethylenetetramine and hexamethoxymethylmelamine.

[10] The resin composition for binders according to any one of [1] to [9], which is used as a binder for road paving materials, waterproofing materials, adhesives, carbon materials, or refractories. [Effects of the Invention]

[0009] According to the present invention, a binder that has excellent compatibility with petroleum heavy oil and is therefore easy to handle can be obtained, and a resin composition for a binder containing a biomass-derived raw material is also provided. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described. In this specification, the expression "a to b" in the description of a range of numerical values ​​means "a or more and b or less" unless otherwise specified. For example, "5 to 90%" means "5% or more and 90% or less."

[0011] [Binder resin composition] The resin composition for binders according to the present embodiment is a resin composition used as a binder in various materials such as asphalt mixtures used in asphalt pavement, refractory materials used in the manufacture of blast furnace refractories, waterproofing materials, adhesives, and carbon materials. The resin composition for a binder of this embodiment (sometimes simply referred to as a "resin composition" in this specification) contains a lignin-modified novolac-type phenolic resin and a hydrophobic hydrocarbon. Each component used in the resin composition of this embodiment will be described below.

[0012] (lignin-modified novolac phenolic resin) The lignin-modified novolac phenolic resin used in the resin composition of this embodiment is a phenolic resin obtained by reacting lignins, phenols, and aldehydes, and having a lignin-derived structure as a structural unit. The lignin-modified novolac phenolic resin used in this embodiment preferably has a weight-average molecular weight of 3,000 or more. Such lignin-modified novolac phenolic resins are compatible with petroleum-based heavy oils such as asphalt and pitch, and can therefore be suitably used to provide liquid binders with excellent handleability and processability.

[0013] In one embodiment, the lignin-modified novolac phenolic resin has a lignin modification rate of 5 to 60%. Since the lignin-modified novolac phenolic resin has a lignin modification rate within the above range, it is a biomass-derived material, and therefore reduces the environmental impact and can have excellent curability.

[0014] (Method of producing lignin-modified novolac phenolic resin) The lignin-modified novolac phenolic resin used in the resin composition of this embodiment is a phenolic resin obtained by reacting lignins, phenols, and aldehydes in the presence of an acid catalyst. More specifically, the lignin-modified novolac phenolic resin can be produced by reacting lignins, phenols, and aldehydes in the presence of an acid catalyst under conditions where the molar ratio of aldehydes to phenols (F / P) is 0.2 or higher, preferably 0.3 to 1.2. The upper limit of the molar ratio (F / P) is preferably 1.1 or lower, more preferably 1.0 or lower. The lower limit of the molar ratio (F / P) is preferably 0.4 or higher, more preferably 0.5 or higher. By carrying out the reaction under conditions where the molar ratio of aldehydes to phenols (F / P) is within the above range, a lignin-modified novolac phenolic resin having a desired weight-average molecular weight and lignin modification rate can be produced.

[0015] The materials and production conditions used in producing the lignin-modified novolac phenolic resin of this embodiment will be described in detail below.

[0016] (phenols) Phenols used to produce the lignin-modified novolac phenolic resin include phenol, phenol derivatives, and combinations thereof. Phenol derivatives can be used in which any substituent has been introduced into the benzene ring. Examples of the substituent include a hydroxyl group, a lower alkyl group such as a methyl group or an ethyl group, a halogen atom such as fluorine, chlorine, bromine, or iodine, an amino group, a nitro group, and a carboxyl group. Specific examples of usable phenols include phenol, catechol, resorcinol, hydroquinone, o-cresol, m-cresol, p-cresol, o-fluorophenol, m-fluorophenol, p-fluorophenol, o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, o-iodophenol, m-iodophenol, p-iodophenol, o-aminophenol, m-aminophenol, p-aminophenol, o-nitrophenol, m-nitrophenol, p-nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol, salicylic acid, p-hydroxybenzoic acid, and combinations thereof. One type of phenol may be used alone, or two or more types may be used in combination.

[0017] As the phenol, alkylphenols having 2 to 18 carbon atoms can also be used. By using such alkylphenols in combination with lignins, the softening point of the resulting lignin-modified novolac phenolic resin can be adjusted, and compatibility can be improved. The alkylphenols may have a branched chain or an unsaturated bond in the alkyl chain. The substitution position of the alkyl chain on the benzene ring may be ortho-, meta-, or para-substituted. Examples of alkylphenols include ethylphenol, propylphenol, isopropylphenol, butylphenol, secondary butylphenol, tertiary butylphenol, amylphenol, tertiary aminophenol, hexylphenol, heptylphenol, octylphenol, tertiary octylphenol, nonylphenol, tertiary nonylphenol, decylphenol, undecylphenol, dodecylphenol, tridecylphenol, tetradecylphenol, pentadecylphenol, cardanol, curd, urushiol, hexadecylphenol, methyl curd, heptadecylphenol, laccol, thiol, and octadecylphenol. Vegetable oils such as cashew nut shell liquid (cashew oil) and urushi extract can also be used as alkylphenols.

[0018] Among these, it is preferable to use one or more phenols selected from the group consisting of phenol, cresol, xylenol, alkylphenols, and bisphenols. From the viewpoint of production costs, it is preferable to use phenol, cresol, butylphenol, and bisphenol A. It is also preferable to use cashew nut shell liquid (cashew oil) and its purified products, as they are derived from biomass.

[0019] (lignins) The lignins used in the production of the lignin-modified novolac phenolic resin include at least one selected from lignin and lignin derivatives. Lignin, along with cellulose and hemicellulose, is a major component of plant structure and one of the most abundant aromatic compounds in nature. Because lignin exists in plants as lignocellulose, a portion of the lignin is bound together, often referring to compounds obtained from plants through decomposition or other processes. Examples include pulp lignins such as kraft lignin, lignosulfonic acid, soda lignin, and soda-anthraquinone lignin; organosolv lignin; lignophenols, which are compounds in which phenol is added to high-temperature, high-pressure water-treated lignin or explosive lignin during extraction with concentrated sulfuric acid; and phenolized lignin. The origin of lignin is not particularly limited, and examples include wood and herbaceous plants that contain lignin and form woody parts, such as conifers such as cedar, pine, cypress, and spruce; broad-leaved trees such as beech, birch, oak, zelkova, and eucalyptus; and grasses (herbaceous plants) such as rice, wheat, corn, and bamboo.

[0020] In this embodiment, the term "lignin derivative" refers to a compound having a unit structure constituting lignin or a structure similar to the unit structure constituting lignin. The lignin derivative has a unit structure of a phenol derivative. This unit structure has chemically and biologically stable carbon-carbon bonds and carbon-oxygen-carbon bonds, and is therefore resistant to chemical deterioration and biological decomposition.

[0021] Examples of lignin derivatives include guaiacylpropane (ferulic acid) represented by formula (A) in the following formula (1), syringylpropane (sinapic acid) represented by formula (B) below, and 4-hydroxyphenylpropane (coumaric acid) represented by formula (C) below. The composition of the lignin derivative varies depending on the biomass used as the raw material. Lignin derivatives containing a guaiacylpropane structure are mainly extracted from coniferous trees. Lignin derivatives containing a guaiacylpropane structure and a syringylpropane structure are mainly extracted from broad-leaved trees. Lignin derivatives containing a guaiacylpropane structure, a syringylpropane structure, and a 4-hydroxyphenylpropane structure are mainly extracted from herbaceous plants.

[0022] [ka]

[0023] The lignin derivative is preferably one obtained by decomposing biomass. Since biomass is formed by capturing and immobilizing carbon dioxide from the atmosphere during the photosynthesis process, biomass contributes to suppressing the increase in carbon dioxide in the atmosphere, and industrial use of biomass can contribute to suppressing global warming. Examples of biomass include lignocellulosic biomass. Examples of lignocellulosic biomass include leaves, bark, branches, and wood of lignin-containing plants, as well as processed products thereof. Examples of lignin-containing plants include the above-mentioned broad-leaved trees, conifers, and herbaceous plants.

[0024] Biomass decomposition methods include chemical treatment, hydrolysis, steam explosion, supercritical water treatment, subcritical water treatment, mechanical treatment, cresol sulfate, and pulp production. From the viewpoint of environmental impact, steam explosion, subcritical water treatment, and mechanical treatment are preferred. From the viewpoint of cost, pulp production is preferred. Furthermore, from the viewpoint of cost, it is preferable to use by-products of biomass utilization. Lignin derivatives can be prepared, for example, by decomposing biomass in the presence of various cooking liquors or solvents at 150 to 400°C, 1 to 40 MPa, and 8 hours or less. Lignin derivatives can also be prepared by methods disclosed in JP 2009-084320 A and JP 2012-201828 A.

[0025] Examples of lignin derivatives include those obtained by decomposing lignocellulose, which is a combination of lignin, cellulose, and hemicellulose. Lignin derivatives may include lignin decomposition products, cellulose decomposition products, hemicellulose decomposition products, and the like, each of which is composed primarily of a compound having a lignin skeleton. Lignin derivatives may also contain inorganic substances derived from biomass or processes. When used in the applications of this embodiment, the content of inorganic substances is preferably 10% by mass or less of the total lignin derivative used.

[0026] The lignin derivative preferably has many reactive sites where the curing agent acts through an electrophilic substitution reaction with the aromatic ring. Since less steric hindrance near the reactive site improves reactivity, it is preferable that at least one of the ortho- and para-positions of the aromatic ring containing a phenolic hydroxyl group is unsubstituted. Preferred lignin derivatives are those derived from conifers or herbs that contain many guaiacyl nucleus or 4-hydroxyphenyl nucleus structures as aromatic units of the lignin. Examples of lignin derivatives that can be used include those disclosed in JP 2009-084320 A and JP 2012-201828 A.

[0027] In addition to the above basic structure, the lignin derivative may be a lignin derivative having a functional group (a secondary lignin derivative).

[0028] The functional groups possessed by the secondary lignin derivatives are not particularly limited, but are preferably those in which two or more of the same functional groups can react with each other or with other functional groups. Specific examples include epoxy groups, methylol groups, and vinyl groups with carbon-carbon unsaturated bonds, ethynyl groups, maleimide groups, cyanate groups, and isocyanate groups. Among these, lignin derivatives into which methylol groups have been introduced (methylolated) are preferred. Such secondary lignin derivatives undergo self-crosslinking through a self-condensation reaction between methylol groups and also crosslink with alkoxymethyl groups and hydroxyl groups in the crosslinking agent described below. As a result, lignin-modified novolac-type phenolic resins with a particularly homogeneous and rigid skeleton and excellent solvent resistance can be obtained.

[0029] Furthermore, the lignin derivative may have a carboxyl group. Lignin obtained by a pulp process or high-temperature, high-pressure water treatment may have a carboxyl group. A lignin-modified novolac phenolic resin obtained from a lignin derivative having a carboxyl group has many crosslinking points for the curing agent described below, and therefore the crosslinking density of the obtained crosslinked product can be improved, resulting in a crosslinked product with excellent solvent resistance.

[0030] In addition, when the above-mentioned lignin derivative has a carboxyl group, the carboxyl group belongs to the carboxyl group. 13 When subjected to C-NMR analysis, this can be confirmed by the presence or absence of absorption peaks at 172 to 174 ppm.

[0031] The lignins used in producing the lignin-modified novolac phenolic resin have a weight-average molecular weight of, for example, 2,000 to 100,000. The lower limit of the weight-average molecular weight is preferably 2,500 or more, more preferably 3,000 or more, and even more preferably 4,000 or more. The upper limit of the weight-average molecular weight is preferably 90,000 or less, more preferably 80,000 or less, and even more preferably 75,000 or less. By using lignins having a weight-average molecular weight within the above range, the resulting lignin-modified novolac phenolic resin has excellent curability. The weight-average molecular weight is a polystyrene-equivalent number-average molecular weight measured by gel permeation chromatography and can be determined by the method in the Examples.

[0032] The number-average molecular weight of the lignins used in producing the lignin-modified novolac phenolic resin is, for example, 200 to 5,000. The lower limit of the number-average molecular weight is preferably 300 or more, more preferably 350 or more, and even more preferably 400 or more. The upper limit of the number-average molecular weight is preferably 4,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less. Lignins having a number-average molecular weight within the above range are preferred because they have excellent reactivity and therefore excellent workability in the production process of the lignin-modified novolac phenolic resin. Furthermore, by using lignins having a number-average molecular weight within the above range, the resulting lignin-modified novolac phenolic resin has excellent curability and the cured product thereof can have high mechanical strength. The number-average molecular weight is the polystyrene-equivalent number-average molecular weight measured by gel permeation chromatography and can be determined by the method described in the Examples.

[0033] Here, an example of a method for measuring the molecular weight by gel permeation chromatography will be described. In a method for measuring molecular weight by gel permeation chromatography, a lignin derivative is first dissolved in a solvent to prepare a measurement sample. The solvent used is not particularly limited as long as it can dissolve the lignin derivative; however, from the viewpoint of measurement accuracy by gel permeation chromatography, for example, tetrahydrofuran or N-methyl-2-pyrrolidone is preferred. Since the lignins of this embodiment may contain insoluble matter due to biomass, process-derived inorganic matter, and high-molecular-weight organic matter derived from plants, the molecular weight of the lignins is determined by selecting an appropriate solvent and filtering the insoluble matter. Furthermore, to increase the lignin modification rate of the resulting lignin-modified novolac phenolic resin, the insoluble matter of the lignins used is preferably 30% by mass or less in an appropriate solvent. Similarly, the molecular weight of the lignin-modified novolac phenolic resin is determined by filtering the insoluble matter. The insoluble matter content of the lignin-modified novolac phenolic resin is preferably 15% by mass or less, more preferably 10% by mass or less. When the content is within the above range, the lignin-modified novolac phenolic resin has good curability, and in particular, can be cured uniformly.

[0034] Next, a GPC system "HLC-8320GPC (Tosoh)" was connected in series with a general-purpose organic column "TSKgel GMHXL (Tosoh)" packed with a styrene-based polymer filler, and a "G2000HXL (Tosoh)." 200 μL of the sample was injected into this GPC system, and the eluent, tetrahydrofuran, was developed at 1.0 mL / min at 40 °C. Retention times were measured using refractive index (RI) and ultraviolet absorbance (UV). The number-average molecular weight and weight-average molecular weight of the target lignins could be calculated from a calibration curve showing the relationship between retention time and molecular weight for a separately prepared standard polystyrene. Refractive index was the preferred detection mode.

[0035] The molecular weight of the standard polystyrene used to prepare the calibration curve is not particularly limited, but for example, standard polystyrenes (manufactured by Tosoh) with weight average molecular weights of 1,090,000, 427,000, 190,000, 96,400, 37,900, 18,100, 10,200, 5,970, 2,630, 1,050, and 500 can be used.

[0036] The lignins used in producing the lignin-modified novolac phenolic resin preferably have a softening point of 90°C or higher, more preferably 110°C or higher, and even more preferably 130°C or higher. On the other hand, lignins whose softening points are too high to be measured can also be used. When such lignins are used to produce a lignin-modified novolac phenolic resin with a high degree of modification, the resulting modified novolac phenolic resin has a high molecular weight, low fluidity, and poor processability. However, the lignin-modified novolac phenolic resin of this embodiment unexpectedly exhibits good processability, despite the high lignin modification rate and high molecular weight of the lignin-modified phenolic resin obtained from such lignins.

[0037] The volatile content of the lignins used is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less. By keeping the volatile content of the lignins within the above range, the reactivity of the lignins can be improved, thereby increasing the reaction rate of the resulting lignin-modified novolac phenolic resin. The main volatile content is often water, which can be calculated by, for example, spreading 4 g of the lignin in an aluminum cup and drying it at 80°C for 20 hours.

[0038] The softening point of lignins can be measured using a ring and ball softening point tester (for example, ASP-MG2 model manufactured by Meltec Co., Ltd.) in accordance with JIS K2207. Note that if the lignin contains a large amount of water, it is measured after being completely dried at 70°C or less. In this embodiment, if a good sample cannot be prepared due to the thermal melting properties of the lignin, for example, using a hot plate at 150 to 200°C, it is determined that the softening point is too high to be measured.

[0039] When using lignins obtained by decomposing biomass, they may contain large amounts of low-molecular-weight components, which can cause volatile content, odor, and a lower softening point when heated. These components can be used as is, or can be removed by heating, drying, or other methods to adjust the softening point and odor.

[0040] (aldehydes) Examples of aldehydes used in producing the lignin-modified novolac phenolic resin include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, polyoxymethylene, chloral, hexamethylenetetramine, furfural, glyoxal, n-butylaldehyde, caproaldehyde, allylaldehyde, benzaldehyde, crotonaldehyde, acrolein, tetraoxymethylene, phenylacetaldehyde, o-tolualdehyde, salicylaldehyde, and paraxylene dimethyl ether. Preferred examples include formaldehyde, paraformaldehyde, trioxane, polyoxymethylene, acetaldehyde, and paraxylene dimethyl ether, as well as combinations thereof. The aldehydes may be used alone or in combinations of two or more. Among these, formaldehyde or acetaldehyde is preferably used from the viewpoints of productivity and cost.

[0041] (acid catalyst) The acid catalyst used in producing the lignin-modified novolac phenolic resin may be any acid that can be used as a reaction catalyst, and organic acids, inorganic acids, and combinations thereof may be used. Examples of organic acids include acetic acid, formic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, benzoic acid, salicylic acid, sulfonic acid, phenolsulfonic acid, paratoluenesulfonic acid, and zinc acetate. Examples of inorganic acids include hydrochloric acid, sulfuric acid, sulfates, phosphoric acid, and phosphates.

[0042] In the production of the lignin-modified novolac phenolic resin, the molar ratio of aldehydes to phenols (F / P) is, for example, 0.2 or more, preferably 0.3 or more, and more preferably 0.4 or more. The upper limit of the molar ratio of aldehydes to phenols (F / P) is, for example, 1.2 or less, preferably 1.1 or less, and more preferably 1.0 or less. By carrying out the reaction under conditions where the molar ratio of aldehydes to phenols (F / P) is within the above range, it is possible to obtain a lignin-modified novolac phenolic resin having a weight-average molecular weight of 3,000 or more and improved processability and strength.

[0043] In the production of the lignin-modified novolac phenolic resin, the step of reacting lignins, phenols, and aldehydes in the presence of an acid catalyst may include the following steps: mixing lignins and phenols under heating at 70 to 120°C to disperse the lignins and obtain a mixture (step 1); mixing an acid catalyst simultaneously with or after step 1 (step 2); and mixing aldehydes after step 2 (step 3). The step of reacting lignins, phenols, and aldehydes in the presence of an acid catalyst is preferably carried out at a temperature of, for example, 60 to 120°C, preferably 80 to 100°C, for a reaction time of, for example, 10 to 100 minutes. This allows the reaction to proceed efficiently and sufficiently. Furthermore, by carrying out the reaction under heating, the starting materials are uniformly mixed, and the resulting lignin-modified novolac phenolic resin can be uniformly cured due to intermolecular entanglement and interactions, thereby achieving molding with excellent dimensional accuracy. The reaction time is not particularly limited and can be determined appropriately depending on the type of starting materials, the molar ratio, the amount and type of catalyst used, and the reaction conditions. Furthermore, the reaction mixture after the reaction may be post-treated. For post-treatment, for example, distillation under heating (e.g., 150°C or higher), distillation under normal pressure, or distillation under reduced pressure, or a combination of these, can be used.

[0044] The above steps 1, 2, and 3 are preferably carried out without a solvent, but an organic solvent or water may be used as the solvent. Instead of adding water, hydrous lignin may be used. Examples of organic solvents include alcohols, ketones, esters, ethers, and hydrocarbons. Examples of alcohols include methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, octanol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and glycerin. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone. Examples of esters include methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, methyl lactate, ethyl lactate, and butyl lactate. Examples of ethers include propyl ether, dioxane, methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methyl carbitol, ethyl carbitol, butyl carbitol, methyl cellosolve acetate, ethyl cellosolve acetate, propyl cellosolve acetate, butyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and propylene glycol monobutyl ether acetate. Examples of hydrocarbons include toluene, xylene, pentane, hexane, cyclohexane, heptane, octane, decane, solvent naphtha, industrial gasoline, petroleum ether, petroleum benzine, and ligroin. These may be used alone or in combination of two or more.

[0045] In the conventional method of increasing the molecular weight of a lignin-modified novolac phenolic resin by adjusting the reaction ratio of phenols, lignins, and aldehydes, the viscosity of the reaction product increases, making dehydration difficult, which can result in a long process time and can also result in a large amount of unreacted phenols remaining. In contrast, the method of the present embodiment can shorten the process time and increase the resin yield compared to conventional methods of increasing the molecular weight by varying the reaction ratio of phenols, lignins, and aldehydes. Furthermore, by setting the molar ratio of aldehydes to phenols (F / P) within the above range and adjusting the molecular weight, molecular weight distribution, and amount of lignins used, the properties of the resulting lignin-modified novolac phenolic resin and the physical properties of the resin material can be adjusted within desired ranges.

[0046] The lignin-modified novolac phenolic resin obtained by the above method has a weight-average molecular weight of 3,000 or more. The weight-average molecular weight of the lignin-modified novolac phenolic resin of this embodiment is, for example, 3,000 to 55,000, preferably 5,500 to 50,000, and more preferably 6,000 to 45,000. A lignin-modified novolac phenolic resin having a weight-average molecular weight within the above range has excellent curing properties, and the cured product thereof has high mechanical strength. Furthermore, the lignin-modified novolac phenolic resin of this embodiment has a lignin modification rate of 5 to 60%, preferably 10 to 55%, and more preferably 20 to 55%. By having a lignin modification rate within the above range, the lignin-modified novolac phenolic resin has excellent compatibility with petroleum heavy oil, and the cured product thereof has excellent strength and heat resistance.

[0047] The softening point of the lignin-modified novolac phenolic resin obtained by the above method is 150°C or lower, preferably 145°C or lower. Lignin-modified novolac phenolic resins having a softening point within the above range have excellent melt-mixability with pitch, asphalt, etc., and their cured products have high mechanical strength. The lower limit of the softening point of the lignin-modified novolac phenolic resin is not particularly limited, but is, for example, 120°C or higher. The softening point of the lignin-modified novolac phenolic resin can be measured in accordance with JIS K2207 using a ring and ball softening point tester (for example, ASP-MG2 model manufactured by Meltec Co., Ltd.).

[0048] The amount of the lignin-modified novolac phenolic resin in the resin composition of this embodiment is, for example, 5 to 95 mass %, preferably 10 to 80 mass %, and more preferably 20 to 70 mass %, based on the total solid content of the resin composition.

[0049] The lignin-modified novolac phenolic resin can be provided in the form of, for example, fine powder, granules, pellets, or varnish, and the form of the lignin-modified novolac phenolic resin can be appropriately selected depending on the application.

[0050] (hydrophobic hydrocarbons) The hydrophobic hydrocarbon used in the resin composition of this embodiment is preferably a heavy oil derived from coal or petroleum, in other words, an aromatic mineral oil that is a residue or extract of crude oil or coal. Specific examples of hydrophobic hydrocarbons include asphalt, coal tar, and coal tar pitch. Examples of asphalt include natural asphalt, petroleum asphalt, petroleum pitch, recycled asphalt, and modified asphalt.

[0051] The amount of the hydrophobic hydrocarbon in the resin composition of this embodiment is, for example, 5 to 95 mass %, preferably 20 to 90 mass %, and more preferably 30 to 80 mass %, based on the total solid content of the resin composition.

[0052] (hardening agent) The resin composition of the present embodiment may contain a curing agent. As the curing agent, it is preferable to use a methylene donor, and specifically, it is preferable to use hexamethylenetetramine or hexamethoxymethylmelamine.

[0053] The content of the curing agent is, for example, 5 to 30 parts by weight, preferably 7 to 25 parts by weight, relative to 100 parts by mass of the lignin-modified novolac phenolic resin. By setting the content within the above numerical range, a resin composition having good curability can be obtained.

[0054] (Method of producing resin composition) The resin composition of the present embodiment is provided as a solid or liquid composition by melt-kneading the lignin-modified novolac phenolic resin, the hydrophobic hydrocarbon, and, if necessary, a curing agent under heating.

[0055] (Application) The resin composition of the present embodiment can be used, for example, as a road paving material, a waterproofing material, an adhesive material, a carbon material, or a binder for refractories. The resin composition of this embodiment can be used as an asphalt binder. The asphalt binder is a binding agent or adhesive that becomes liquid at high temperatures. When asphalt binders are used for road paving, an asphalt mixture is obtained by mixing the asphalt binder with aggregates (e.g., gravel, stones, sand) at a temperature at which the asphalt binder flows (approximately 80 to 150°C). This asphalt mixture is then transported to the road to be paved, laid on the road, and compacted and rolled with a road roller or the like to spread and level the road surface.

[0056] The asphalt binder made of the resin composition of this embodiment is used not only for road paving but also as a waterproofing material for preventing water leakage on the roofs of houses and concrete buildings, etc. Such waterproofing work involves a construction method in which heated and melted asphalt binder is sprayed or poured into the area where waterproofing treatment is desired to form a waterproof layer.

[0057] In addition to the above applications, the asphalt binder made of the resin composition of this embodiment is used as an adhesive, a carbon material, or a refractory material.

[0058] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Example]

[0059] EXAMPLES The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these.

[0060] [Preparation of lignin derivatives or lignin-modified phenolic resins] (Preparation Example 1) (Preparation of Lignin Derivative A1) A lignin derivative was prepared according to the following procedure. 1500 parts by weight of cedar wood flour with a moisture content of 50% was charged into a 10 L stainless steel autoclave with 5000 parts by weight of pure water as cooking liquor, 150 parts by weight of sodium hydroxide, 80 parts by weight of sodium sulfide, 70 parts by weight of sodium carbonate, and 7.5 parts by weight of 9,10-anthraquinone as cooking aid. The cooking reaction was carried out at 170 °C for 3 hours with stirring. After the reaction, the cooking liquor was cooled to room temperature, the pulp components were removed through a screen, and the black liquor containing lignin was separated. The separated black liquor was adjusted to pH 8 with dilute sulfuric acid, and the resulting precipitate was centrifuged. After washing twice with 500 parts by weight of water, the precipitate was suspended in five times the volume of water and readjusted to pH 2 with dilute sulfuric acid. The precipitated lignin was centrifuged again, washed with water, filtered under suction, spread on a tray, air-dried, and then dried in a vacuum oven at 80°C or below, yielding 140 to 150 parts by weight (solid content equivalent) of brown powdered alkaline lignin (lignin derivative A1) with a solid content of 70% or more. The solid content of the lignin was calculated from the residual fraction after placing a 4g sample in an aluminum cup and drying it by heating at 135°C for 1 hour.

[0061] (Preparation Example 2) (Preparation of lignin derivative A2) Beech wood flour with a moisture content of 50% was cooked at 195°C for 1 hour using 3,000 parts by weight of ethanol and 2,250 parts by weight of water as the cooking liquor, and the aqueous solution obtained by fractionating the ethanol from the cooking liquor was centrifuged and freeze-dried to obtain lignin derivative A2 with a solid content of 90% or more, in the same manner as in Preparation Example 1.

[0062] (Preparation Example 3) (Preparation of lignin derivative A3) Lignin derivative A3 was obtained in the same manner as in Preparation Example 1, except that 5,000 parts by weight of pure water, 150 parts by weight of sodium hydroxide, 80 parts by weight of sodium sulfide, and 70 parts by weight of sodium carbonate were used as the cooking liquor, and 7.5 parts by weight of 9,10-anthraquinone was used as the cooking aid. (Preparation of Lignin-Modified Phenolic Resin B3) Subsequently, lignin-modified phenolic resin B3 was synthesized according to the following procedure. 100 parts by weight of phenol was added to a four-neck flask equipped with a stirrer, a condenser, and a thermometer, and 37.4 parts by weight of the solid content of lignin derivative A3 was gradually added and mixed and dispersed at 60°C or higher. 1.5 parts by weight of oxalic acid was added, and 51.2 parts by weight of a 37% aqueous formaldehyde solution was gradually added over 60 minutes and reacted at 100°C. After the addition, the mixture was reacted at 100°C for 60 minutes, and the temperature was raised to 150°C or higher by dehydration at normal pressure and reduced pressure. When the phenol concentration reached 0.7%, the mixture was removed and 124.2 parts by weight of lignin-modified phenolic resin B3 (lignin modification rate 31%) was obtained.

[0063] (Preparation Example 4) (Preparation of Lignin Derivative A3) Lignin derivative A3 was obtained in the same manner as in Preparation Example 3. (Preparation of Lignin-Modified Phenolic Resin B4) Subsequently, lignin-modified phenolic resin B4 was synthesized according to the following procedure. 100 parts by weight of phenol was added to a four-neck flask equipped with a stirrer, a condenser, and a thermometer, and 32.8 parts by weight of the solid content of lignin derivative A3 was gradually added and mixed and dispersed at 60°C or higher. 1.5 parts by weight of oxalic acid was added, and 49.2 parts by weight of a 37% aqueous formaldehyde solution was gradually added over 60 minutes and reacted at 100°C. After the addition, the mixture was reacted at 100°C for 60 minutes, and the temperature was raised to 150°C or higher by dehydration at normal pressure and reduced pressure. When the phenol concentration reached 4%, the mixture was removed and 122.3 parts by weight of lignin-modified phenolic resin B4 (lignin modification rate 28%) was obtained.

[0064] (Preparation Example 5) (Preparation of Lignin Derivative A3) Lignin derivative A3 was obtained in the same manner as in Preparation Example 3. (Preparation of Lignin-Modified Phenolic Resin B5) Subsequently, lignin-modified phenolic resin B5 was synthesized according to the following procedure. A four-neck flask equipped with a stirrer, a condenser, and a thermometer was charged with 100 parts by weight of phenol, and 35.8 parts by weight of the solid content of lignin derivative A3 was gradually added and mixed and dispersed at 60°C or higher. 53.0 parts by weight of cashew shell oil was added and mixed, and then 1.5 parts by weight of 98% sulfuric acid was added. 53.9 parts by weight of a 37% aqueous formaldehyde solution was gradually added over 60 minutes and reacted at 100°C. After the addition, the mixture was reacted at 100°C for 60 minutes. After the addition, the mixture was heated to 140°C or higher by atmospheric dehydration, 46 parts by weight of 25% sodium hydroxide was gradually added to neutralize it, and the mixture was heated to 150°C or higher by reduced pressure dehydration until the phenol concentration reached less than 1%. The mixture was then discharged, yielding 172.3 parts by weight of lignin-modified phenolic resin B5 (lignin modification rate: 21%, cashew modification rate: 30%).

[0065] (Preparation Example 6) (Preparation of lignin derivative A6) Beech wood flour with a moisture content of 50% was cooked at 195°C for 1 hour using 3,000 parts by weight of ethanol and 2,250 parts by weight of water as the cooking liquor, and the aqueous solution obtained by fractionating the ethanol from the cooking liquor was centrifuged and freeze-dried to obtain lignin derivative A6 with a solid content of 90% or more, in the same manner as in Preparation Example 1. (Preparation of lignin-modified phenolic resin B6) 100 parts by weight of phenol was added to a four-neck flask equipped with a stirrer, a condenser, and a thermometer, and 37.4 parts by weight of the solid content of lignin derivative A6 was gradually added and mixed and dispersed at 60°C or higher. 1.5 parts by weight of oxalic acid was added, and 51.2 parts by weight of a 37% aqueous formaldehyde solution was gradually added over 60 minutes to react at 100°C. After the addition, the mixture was reacted at 100°C for 60 minutes, and the temperature was raised to 150°C or higher by dehydration at normal pressure and reduced pressure. When the phenol concentration reached 0.5%, the mixture was removed, yielding 122.8 parts by weight of lignin-modified phenolic resin B6 (lignin modification rate 31%).

[0066] (Preparation Example 7) (Preparation of Lignin Derivative A3) Lignin derivative A3 was obtained in the same manner as in Preparation Example 3. (Preparation of Lignin-Modified Phenolic Resin B7) Subsequently, lignin-modified phenolic resin B7 was synthesized according to the following procedure. 100 parts by weight of phenol was added to a four-neck flask equipped with a stirrer, a condenser, and a thermometer, and 94.9 parts by weight of the solid content of lignin derivative A3 was gradually added and mixed and dispersed at 60°C or higher. 1.5 parts by weight of oxalic acid was added, and 1.5 parts by weight of a 37% aqueous formaldehyde solution was gradually added over 60 minutes and reacted at 100°C. After the addition, the mixture was reacted at 100°C for 60 minutes, and the temperature was raised to 150°C or higher by dehydration at normal pressure and reduced pressure. When the phenol concentration reached less than 1%, the mixture was removed and 180.2 parts by weight of lignin-modified phenolic resin B7 (lignin modification rate 53%) was obtained.

[0067] [Physical properties of lignin derivatives / lignin-modified phenolic resins] The softening points of the lignin derivatives A1 and A2 and the lignin-modified phenolic resins B3 to B7 obtained in the above Preparation Examples were measured by the following method. The results are shown in Table 1. (Method for measuring softening point) The softening points of the target lignin derivatives or lignin-modified phenolic resins were measured using a ring and ball softening point tester (Model ASP-MG2 manufactured by Meltec Co., Ltd.) in accordance with JIS K2207.

[0068] [Examples 1 to 4, Comparative Examples 1 to 3] (Production of Resin Composition) Resin compositions were produced using the lignin derivatives A1 and A2 or novolac-modified phenolic resins B3 to B7 obtained above. The components and amounts used in each example are shown in Table 1. (Performance evaluation of resin composition) The resin compositions obtained in each example were evaluated for the following items. (compatibility, uniform appearance) In each example, the lignin derivative or lignin-modified phenolic resin was mixed with solid pitch at 165°C using a spatula. The state of the mixture was visually inspected and evaluated according to the following criteria. The results are shown in Table 1. A: The lignin-modified phenolic resin / lignin derivative and solid pitch are compatible with each other, resulting in a liquid mixture. B: The lignin-modified phenolic resin / lignin derivative and the solid pitch do not mix together, and a mixture with remaining solids is obtained. (fixed carbon) The fixed carbon content (%) of the resin composition was measured in accordance with JIS K 6910. In Comparative Examples 1 and 2, the non-uniformity was large, so measurements were taken at the melted portions, and the results are shown in Table 1. A decrease of 5% or more in fixed carbon was observed in portions with a high solid content. The higher the fixed carbon content, the better the heat resistance, which is preferable for road paving materials, waterproofing materials, adhesives, carbon materials, or refractories.

[0069] [Table 1]

[0070] As shown in Table 1, lignin-modified phenolic resins exhibit high compatibility with solid pitch and have a high fixed carbon content, making them useful as environmentally friendly binders for road paving materials, waterproofing materials, adhesives, carbon materials, or refractories.

Claims

1. A resin composition for binders, comprising a lignin-modified novolac-type phenolic resin and a hydrophobic hydrocarbon.

2. 2. The resin composition for binders according to claim 1, wherein the lignin-modified novolac phenolic resin has a lignin modification rate of 5% or more and 60% or less.

3. 2. The resin composition for binders according to claim 1, wherein the lignin-modified novolac phenolic resin has a softening point of 150°C or lower.

4. The binder resin composition according to claim 1 , wherein the hydrophobic hydrocarbon contains an aromatic ring.

5. The resin composition for binders according to claim 1 , wherein the hydrophobic hydrocarbon comprises a residue or extract of crude oil or coal.

6. The hydrophobic hydrocarbons include asphalt, coal tar, and coal tar pitch. The binder resin composition according to claim 1 .

7. The resin composition for binders according to claim 6, wherein the asphalt is at least one selected from the group consisting of natural asphalt, petroleum asphalt, petroleum pitch, recycled asphalt, and modified asphalt.

8. The resin composition for binders according to claim 1 , further comprising a curing agent.

9. The resin composition for binders according to claim 8 , wherein the curing agent comprises at least one selected from hexamethylenetetramine and hexamethoxymethylmelamine.

10. The resin composition for binders according to any one of claims 1 to 9, which is used as a binder for road paving materials, waterproofing materials, adhesives, carbon materials, or refractories.

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