JPH05265256A - Negative charging toner for electrostatic image development - Google Patents

Abstract

(57) [Abstract] [Purpose] The triboelectrification property is stable, the triboelectrification amount distribution is sharp and uniform, the rise of charge and environmental stability are good, and the charge amount is controlled to suit the developing system used. To provide a toner that can. A negatively-chargeable toner for developing an electrostatic image, comprising a polyester containing an alcohol component (A) and / or (B) represented by the following general formula as a condensation component as a charge control agent. [Chemical 1]

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic printing and the like, and more particularly to a negatively charging developing toner.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 61-147261, the method of developing an electrostatic image with toner is roughly classified into so-called two-component system in which toner and carrier are mixed. There are a method of using a developer and a method of using a one-component developer which is used alone as a toner without being mixed with a carrier.

In the above-mentioned method, the toner and the carrier are agitated and frictionally charged so that they are charged to different polarities, and the electrostatically charged image having the opposite polarity is visualized by the charged toner. Depending on the type of carrier, magnet brush method using iron powder carrier,
There are a cascade method using a bead carrier, a fur brush method, and the like.

The latter one-component developing method includes a powder cloud method in which toner particles are sprayed and a contact developing method in which toner particles are directly brought into contact with an electrostatic latent image surface for development (also referred to as touchdown development). In other words, there is an induction developing method in which a magnetic conductive toner is brought into contact with the electrostatic latent image surface.

As the toner applied to these various developing methods, fine powder in which a colorant such as carbon black is dispersed in a binder resin made of natural resin or synthetic resin is used. For example, particles in which a colorant is dispersed in a binder resin such as polystyrene and finely pulverized to about 1 to 30 μm are used as toners. Further, a magnetic toner such as those containing a magnetic material such as magnetite is used as a magnetic toner.

As described above, the toner used in various developing methods has a positive or negative charge depending on the polarity of the electrostatic charge image to be developed. To make the toner have a charge, It is possible to utilize the triboelectric charging property of the resin which is a component of the toner, but since the toner has a low charging property in this method, the image obtained by development tends to be fogged and unclear. Therefore, in order to impart a desired triboelectric chargeability to the toner, a dye that imparts a chargeability,
A pigment or a charge control agent has been added.

Conventionally, as negative charge control agents, metal complex salts of monoazo dyes, nitrohumic acid and its salts, metal complexes of salicylic acid, naphthoic acid, dicarboxylic acids such as Co, Cr and Fe, sulfonated copper phthalocyanine pigments, There are nitro groups, halogen-introduced styrene oligomers, chlorinated paraffins, melamine resins, and the like, but these dyes have a complicated structure, the properties are not constant, and the stability is poor. Further, during thermal kneading, decomposition, mechanical shock, friction, changes in temperature and humidity conditions, and the like are likely to cause decomposition or deterioration, and a phenomenon in which charge controllability is deteriorated is likely to occur. In many cases, the chargeability changes depending on the environment. Furthermore, when a conventional toner containing the charge control agent is used for a long time, filming may occur on the photoconductor due to poor charging.

Further, recently, polyester resins and epoxy resins have been often used as binder resins because of their advantages such as resistance to vinyl chloride matt fusion and the fact that they do not impair the original color of the color material of the color toner. However, when a polyester resin or epoxy resin is used as a binder resin in a toner, in any case, even if the charge amount is low, or even if it is high, repeated use reduces the charge amount, causing fog and toner scattering. There was a problem that it was difficult to do. This is because the polyester resin and epoxy resin have a chemical structure of -COO.
It is considered that the functional groups such as H and —OH groups remain, which hinders maintaining stable chargeability.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to ensure stable triboelectric charging between toner particles, between toner and carrier, toner in the case of one-component development and a charging member such as a developing sleeve or a blade. Further, the triboelectric charge amount distribution is sharp and uniform, the charge rising property and the environmental stability are good, and it is to provide a toner capable of controlling the charge amount suitable for the developing system to be used. It is another object of the present invention to provide a vivid color toner, and yet another object thereof to provide a toner which is free from background stains and toner scattering and which can provide an image with high fidelity equivalent to the initial image even when continuously used.

[0010]

As a result of intensive studies, the present inventors have found that in a toner containing a binder resin, a colorant and a charge control agent as main components, an alcohol component (A) represented by the following general formula and By incorporating a polyester containing / or (B) as a condensation component as a charge control agent, a negatively chargeable toner for developing an electrostatic charge image, which improves the above-mentioned conventional defects, can be obtained.

The negatively chargeable toner charge control agent for developing an electrostatic image includes a polyester containing a alcohol component (A) and / or (B) represented by the following general formula as a condensation component and a metal-containing azo dye. When it was contained as a control agent, a toner having a better negative chargeability was obtained, and the binder resin was also good when it was a polyester resin or an epoxy resin.

[0012]

[Chemical 2]

In particular, when the polyester containing the alcohol component (A) and / or (B) represented by the general formula as a condensation component is contained in the toner containing the polyester or the epoxy resin as the main binder, good electrostatic image development is achieved. Toner is obtained.

Examples of the alcohol component of the general formula in the present invention include those having the following structures.

In the present invention, the following carboxylic acids can be used when a polyester resin is obtained by polycondensing an alcohol component of the above general formula and a polyvalent carboxylic acid.

For example, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, and carbon A divalent organic acid monomer substituted with a saturated or unsaturated hydrocarbon group of the number 3 to 22, an acid anhydride thereof, a dimer of a lower alkyl ester and linoleic acid,
Other divalent organic acid monomers can be mentioned.

Next, some production examples of the polyester resin containing the alcohol component (A) and / or (B) of the general formula of the present invention as a condensation component will be shown. These synthetic examples are
It can be performed by a known means.

Production Example 1 Exemplified alcohol of the following formula (A-1) 10 wt% Bis (4-hydroxyphenyl) sulfone 18 wt% Hexamethylene diisocyanate 10 wt% Adipic acid 37 wt% Butylene glycol 25 wt%

[0019]

[Chemical 3]

These mixtures were heated and stirred at 210 ° C. for about 6 hours, cooled to room temperature after completion of the reaction, and polyester resin A was added.
(Mw = 10000, Mw / Mn = 3) was obtained.

Production Example 2 Exemplified alcohol (A-1) 10 wt% Bis (4-hydroxyphenyl) sulfone 10 wt% Hexamethylene diisocyanate 12 wt% Adipic acid 40 wt% Butylene glycol 28 wt% These mixtures are heated and stirred at 200 ° C. for about 7 hours. Then, after completion of the reaction, the mixture was cooled to room temperature, and polyester resin B (Mw = 80
00, Mw / Mn = 3) was obtained.

The amount of the polyester used as the charge control agent in the present invention is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method. Although it is not uniquely limited, it is preferably used in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the binder resin. If the amount is less than 0.1 parts by weight, the negative charging of the toner will be insufficient, which is not practical. On the other hand, when the amount exceeds 20 parts by weight, the chargeability of the toner is too large and the electrostatic attraction with the carrier increases, resulting in a decrease in the fluidity of the developer and a decrease in the image density.

As the metal-containing azo dye used as a negative charge control agent together with the polyester containing the alcohol components (A) and (B) represented by the above general formula, all commercially available products can be used. .. Examples include, but are not limited to, Eisenspiron Black TRH manufactured by Hodogaya Chemical Co., Ltd., Eisencolor T-37, 77, and Bontron S-32, 34, 40, 44 manufactured by Orient Chemical Co., Ltd. As the binder resin used in the present invention, polystyrene, poly-p-chlorostyrene,
A homopolymer of styrene such as polyvinyltoluene and its substitutes; a styrene-p-chlorostyrene copolymer, a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, a styrene-vinylnaphthalene copolymer, a styrene-acryl. Methyl acid copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer , Styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene- Styrene-based copolymers such as maleic acid copolymers and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, epoxy resin , Polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpen resin,
Phenolic resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes, etc. may be used alone or in combination.

In particular, as examples of the binder resin suitable for pressure fixing, the following resins can be used alone or in combination.

Polyolefin (low molecular weight polyethylene,
Low molecular weight polypropylene, polyethylene oxide, polytetrafluoroethylene, etc.), epoxy resin, polyester resin,
Styrene-butadiene copolymer (monomer ratio 5 to 30:
95-70), olefin copolymer (ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-vinyl chloride copolymer Polymer, ethylene-vinyl acetate copolymer, ionomer resin), polyvinylpyrrolidone, methyl vinyl ether-
Examples include maleic anhydride copolymers, maleic acid-modified phenolic resins, phenol-modified terpene resins and the like.

In particular, the polyester resin used in the present invention is obtained by polycondensation of alcohol and carboxylic acid, and examples of the alcohol include polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol,
Diols such as neopentyl glycol and 1,4-butenediol, ethers such as 1,4-bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropyleneated bisphenol A, etc. Bisphenols, divalent alcohol units obtained by substituting these with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms, other divalent alcohol units, sorbitol,
1,2,3,6-hexanetetrol, 1,4-salbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol , 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and other trihydric or higher polyhydric alcohol monomers Can be mentioned. Further, as the carboxylic acid used to obtain the polyester resin, for example, palmitic acid, stearic acid, monocarboxylic acid such as oleic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid. , Isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, and divalent organic acid monomers obtained by substituting these with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms. , Anhydrides of these acids, dimers of lower alkyl esters and linoleic acid, other divalent organic acid monomers, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1, 2, 4
-Cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,
5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-
Examples include trivalent or higher polyvalent carboxylic acid monomers such as octane tetracarboxylic acid embol trimer acid and anhydrides of these acids.

Furthermore, the epoxy resin used in the present invention is a polycondensation product of bisphenol A and epichlorohydrin, for example, Epomic R36.
2, R364, R365, R366, R367, R36
9 (above Mitsui Petrochemical Industry Co., Ltd.), Epotote YD
-011, YD-012, YD-014, YD-90
4, YD-017 (all manufactured by Tohto Kasei Co., Ltd.), Epicoat 1002, 1004, 1007 (all manufactured by Shell Chemical Co., Ltd.), and other commercially available products.

As the colorant used in the present invention, carbon black, lamp black, iron black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, hansa yellow G, rhodamine 6
G, lake, chalco oil blue, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, dyes and pigments may be used alone or in combination. obtain.

Further, when the toner of the present invention is used as a two-component type developer, it is used as a mixture with carrier powder.

As the carrier that can be used in the present invention, all known carriers can be used, for example, magnetic powder such as iron powder, ferrite powder, nickel powder, glass beads and the like, and the surface thereof such as resin. And the like.

Further, the toner of the present invention further contains a magnetic material and can be used as a magnetic toner. Examples of the magnetic material contained in the magnetic toner of the present invention include iron oxides such as magnetite, hematite and ferrite, metals such as iron, cobalt and nickel, or aluminum of these metals,
Examples include alloys of metals such as cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof.

These ferromagnetic materials have an average particle size of 0.1 to 2
It is desirable that the amount is about 20 μm to 100 parts by weight of the resin component, particularly preferably 40 to 100 parts by weight of the resin component.
It is 150 parts by weight.

Further, the toner of the present invention may be mixed with additives as required. Examples of the additives include lubricants such as Teflon and zinc stearate, abrasives such as cerium oxide and silicon carbide, fluidity imparting agents such as colloidal silica and aluminum oxide, anti-caking agents, or carbon black, tin oxide. And the like, or a fixing aid such as a low molecular weight polyolefin.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. All parts are parts by weight.

[0035]

【Example】

Example 1 Styrene-2-ethylhexyl acrylate copolymer 80 parts Polypropylene 5 parts C.I. I. Pigment Blue 15 5 parts Polyester Resin A (Production Example 1) 20 parts After thoroughly stirring and mixing the mixture having the above composition in a Henschel mixer, it is about 3 at a temperature of 130 to 140 ° C. in a roll mill.
After heating and melting for 0 minutes and cooling to room temperature, the obtained kneaded product was pulverized and classified to obtain a blue toner having a particle size of 5 to 20 μm.

2.5 parts of this toner was mixed with 97.5 parts of a 100-250 mesh ferrite carrier coated with a silicone resin in a ball mill to obtain a developer.

Next, the above developer was set on FT4060 manufactured by our company and developed, and a good image was obtained, and the image did not change even after 200,000 images were printed.

When the toner charge amount was measured by the blow-off method, the initial charge amount was -19.5 μC / g, and the toner charge amount after running 100,000 sheets was-.
There was almost no difference from the initial value of 18.1 μC / g.
Also, in a high humidity environment of 35 ° C 90% RH and at 10 ° C 1
Even under a low humidity environment of 5% RH, an image equivalent to normal humidity was obtained.

There was also no toner filming on the photosensitive member.

Example 2 Styrene-2-ethylhexyl acrylate copolymer 80 parts Polypropylene 5 parts Carbon black 10 parts Polyester resin A 1 part Metal-containing monoazo dye (Hodogaya Kagaku Spiron Black TRH) The above raw material mixture was used as an example. Melt kneading, as in 1.
After cooling, crushing and classification, a black toner having a particle size of 5 to 25 μm was obtained.

2.5 parts of this toner was mixed with 97.5 parts of 100-250 mesh ferrite carrier coated with a silicone resin in a ball mill to obtain a developer.

Next, this developer was set in a copying machine FT4060 manufactured by our company as in Example 1 and an image test was conducted. As with Example 1, a good image with high sharpness was obtained. The image remained the same even after 100,000 images were printed.

When the toner charge amount was measured by the blow-off method, the initial charge amount was −22.6 μC / g, and the toner charge amount after running 100,000 sheets was −.
There was almost no difference from the initial value of 20.3 μC / g.
Also, in a high humidity environment of 35 ° C 90% RH and at 10 ° C 1
Even under a low humidity environment of 5% RH, an image equivalent to normal humidity was obtained.

There was also no toner filming on the photosensitive member.

Comparative Example 1 A developer was obtained and an image test was conducted in the same manner as in Example 1 except that zinc salicylate (E-84 manufactured by Orient Chemical Industry Co., Ltd.) was used in place of the polyester resin A of Example 1.
The initial image was a clear image without fog, but 1
From around 0,000 sheets, an unclear image with fog was formed, and toner filming was observed on the surface of the photoconductor. Also, 35
When an image test was carried out in a high humidity environment of 90 ° C. and RH, an image density as low as 0.95 was obtained, and an unclear image with fog was obtained.

When the charge amount was measured in the same manner as in Example 1, the initial charge amount was -15.5 μC / g, but it decreased to -7.8 μC / g after 100,000 sheets. It was

Example 3 Epoxy resin (R365 manufactured by Mitsui Petrochemical Co., Ltd.) 80 parts Epoxy resin (YD-017 manufactured by Tohto Kasei Co., Ltd.) 20 parts C.I. I. Pigment Blue 15 5 parts C.I. I. Pigment Yellow 175 5 parts Polyester Resin B (Production Example 2) 15 parts In the same manner as in Example 1, after thoroughly stirring and mixing in a Henschel mixer, 130 to 1 with a roll mill.
After heating and melting at a temperature of 40 ° C. for about 30 minutes and cooling to room temperature, the obtained kneaded product was pulverized and classified to obtain a green toner having a particle diameter of 5 to 20 μm. To 100 parts of this toner, 3 parts of silicon carbide (particle size: 2 μm) and 0.1 part of hydrophobic colloidal silica were sufficiently stirred and mixed with a speed kneader to obtain a toner.

When this toner was loaded into a developing device as shown in FIG. 1, continuous copying was carried out, and an image test was conducted, a good image was obtained. The image did not change after 50,000 images were printed.

This developing method will be described. As shown in the drawing, the toner 6 contained in the toner tank 7 is forced to the sponge roller 4 by the stirring blade 5, and the toner is supplied to the sponge roller 4. And
The toner taken into the sponge roller 4 is rotated by the sponge roller in the direction of the arrow, so that the toner conveying member 2
Transported to, rubbed, electrostatically or physically adsorbed,
The toner conveying member 2 strongly rotates in the direction of the arrow, and the elastic blade 3 forms a uniform thin toner layer and is triboelectrically charged. After that, the toner is conveyed to the surface of the electrostatic latent image carrier 1 which is in contact with or in the vicinity of the toner conveying member 2, and the latent image is developed.

The electrostatic latent image is formed by exposing the organic photoconductor to 800 V of negative DC, exposing it to form a latent image, and reversal development.

Further, in order to measure the specific charge amount Q / M of the toner on the toner conveying member, the toner on the toner conveying member is sucked through a Faraday cage equipped with a filter layer on the outlet side to When the Q / M was measured by a suction method specific charge amount measuring device for measuring the specific charge of the toner trapped inside, it was confirmed that the toner was sufficiently charged with −9.2 μC / g.

In addition, the charge amount in running 50,000 sheets is −
There was almost no difference between the initial value and 7.6 μC / g.

Also, image quality equivalent to normal humidity was obtained under high and low humidity. Further, there was no toner filming on the photoconductor.

Example 4 Polyester resin 100 parts (Luna Pale 1447 manufactured by Arakawa Chemical Co., Ltd.) Polypropylene 5 parts Carbon black 10 parts Polyester resin A 10 parts Metal-containing monoazo dye 1 part (Orient Chemical Industries S-34) Raw material mixture having the above composition In the same manner as in Example 1, melt kneading,
After cooling, crushing and classification, a black toner having a particle size of 5 to 25 μm was obtained.

2.5 parts of this toner was mixed with 97.5 parts of 100-250 mesh ferrite carrier coated with silicone resin in a ball mill to obtain a developer.

Next, this developer was set in a copying machine FT4060 manufactured by our company as in Example 1 and an image test was conducted. As with Example 1, a good image with high fidelity was obtained. The image remained the same even after 100,000 images were printed.

When the toner charge amount was measured by the blow-off method, the initial charge amount was −20.6 μC / g, and the toner charge amount after running 100,000 sheets was −
There was almost no difference from the initial value of 20.1 μC / g.
Also, in a high humidity environment of 35 ° C 90% RH and at 10 ° C 1
Even under a low humidity environment of 5% RH, an image equivalent to normal humidity was obtained.

Further, there was no toner filming on the photosensitive member.

Comparative Example 2 A toner was prepared in the same manner as in Example 4 except that the polyester resin A of Example 4 was omitted, and an image test was conducted. The initial image was a little fogged and a poor image was obtained. From around the 5,000th sheet, the fog increased and the image became unclear. Also,
When an image test was carried out in a high humidity environment of 35 ° C. and 90% RH, the image density was as low as 0.86 and fog also occurred.

When the charge amount was measured in the same manner as in Example 2, the initial charge amount was as low as -9.5 μC / g, and after 5,000 sheets, it was as low as -1.8 μC / g. ..

Example 5 Polyester resin 100 parts (Luna Pale 1447 manufactured by Arakawa Chemical Co., Ltd.) Candelilla wax 102 (manufactured by Noda Wax Co.) 5 parts C.I. I. Pigment Red 57 5 parts C.I. I. Pigment Red 48 3 parts Polyester resin B 15 parts The mixture having the above composition was sufficiently stirred and mixed in a Henschel mixer in the same manner as in Example 1, and then 110 to 1 by a roll mill.
After heating and melting at a temperature of 20 ° C. for about 40 minutes and cooling to room temperature, the obtained kneaded product was pulverized and classified to obtain a red toner having a particle diameter of 5 to 20 μm. To 100 parts of this toner, 3 parts of silicon carbide (particle size: 2 μm) and 0.1 part of hydrophobic colloidal silica were sufficiently stirred and mixed with a speed kneader to obtain a toner.

This toner was developed in the same developing device as in Example 3 in the same manner and an image test was carried out. As a result, a clear and good image was obtained, and the image did not change after 50,000 sheets were printed. ..

When Q / M was measured by the suction method specific charge amount measuring device in the same manner as in Example 3, the initial value was −8.6 μm.
It showed a sufficient charge of C / g, and the charge amount in running 50,000 sheets was -7.8 μC / g, which was almost the same as the initial value.

Further, image quality equivalent to normal humidity was obtained even under high humidity and low humidity. Further, there was no toner filming on the photoconductor.

Examples 6 to 9 Toners were obtained in the same manner as in Example 1 with the developer compositions shown in the following table. The imageability and chargeability of these toners are also summarized in Table 1.

[0066]

[Table 1]

[0067]

As described above, by using the specific compound of the present invention as a charge control agent, an image having the same quality as the initial image can be obtained even after continuous copying, and stable negative friction is obtained. A toner having a charging property is obtained. Further, a toner having excellent dispersibility in a binder resin and excellent environmental stability can be obtained, and a clear color image can be obtained.

Claims (3)

[Claims] 1. A negatively chargeable toner for developing an electrostatic charge image, comprising a polyester containing an alcohol component (A) and / or (B) represented by the following general formula as a condensation component as a charge control agent. .. [Chemical 1] 2. The negatively-chargeable toner for developing an electrostatic image according to claim 1, further comprising a metal-containing azo dye. 3. The negatively chargeable toner for developing an electrostatic image according to claim 1, wherein the binder resin is a polyester resin or an epoxy resin.