JPS6063221A - Electron beam-curable resin - Google Patents

Abstract

PURPOSE:To obtain the titled resin with great affinity for magnetic powder, useful as binder for magnetic coatings, by adding a specific compound to a polyesterpolyurethane derived from specific copolyester and triisocyanate. CONSTITUTION:An addition polymerization is carried out between (A) a copolyester in which the carboxylic acid component carrying sulfonic acid metal salt group accounts for 0.2-30mol% in the total carboxylic acid component, along with hydroxyl groups at its both molecular ends and (B) a triisocyanate with one isocyanate group less reactive than the other two so that the reaction ratio M of the component (B) to the component (A) is larger than 1 but smaller than 2 to form a polyesterpolyurethane with both ends and side chain carrying isocyanate groups followed by adding to said polyesterpolyurethane (C) a compound having both double bond and at least one active hydrogen atom, thus obtaining the objective resin.

Description

[Detailed description of the invention] The present invention relates to an electron beam curable resin.

BACKGROUND ART Conventionally, six-mode resins have been synthesized in which double bonds in molecules are cleaved by irradiation with electron beams, and bonds are formed between molecules to form crosslinks of a mesh structure.

The present inventor provided a magnetic recording medium using an electron beam curable resin as a binder in Japanese Patent Application No. 57-187683. This electron beam curable resin is made of polyester-based urethane acrylate, and a sulfonic acid metal base that has good affinity with magnetic powder is bonded to the side of the molecule, and multiple double bonds are attached to each end of the molecule. Existing.

By chemically modifying the resin, we aim to improve the dispersibility of the magnetic powder when preparing the magnetic paint and the strength of the magnetic coating after electron beam irradiation. However, since this electron beam curable resin has double bonds only at the ends, the higher the molecular weight, the lower the crosslinking density, resulting in insufficient mechanical strength, solvent resistance, etc. of the coating film. .

Therefore, in order to improve this drawback, the present inventor conducted further intensive research, and as a result, the chain length of a copolymerized polyester having hydroxyl groups at both ends of the molecule was extended using a triinocyanate compound having 6 isocyanate groups in the molecule. After forming a high molecular weight polyisocyanate compound having five or more isocyanate groups in the molecule, it is reacted with a compound having an active hydrogen atom and one or more double bonds in the molecule to form a side chain. They also succeeded in obtaining an electron beam curable resin having a double bond, leading to the present invention.

That is, the electron beam curable resin according to the present invention is an electron beam curable resin obtained by adding the following component (Q) to a polyester polyurethane which is composed of the following components and the following components and has incyanate groups at both ends and side chains. It is a curable resin.

(5) A copolymerized polyester containing 0.2 to 60 moles of carboxylic acid having a sulfonic acid metal base based on the total carboxylic acid component and having hydroxyl groups at both ends of the molecule.

(9) A triisocyanate compound having six isocyanate groups, one of which is inferior in reactivity to the other two isocyanate groups.

(Q1 A compound having at least one active hydrogen atom and a double bond.

The copolymerized polyester, which is component (5) of this invention, can be obtained by copolymerizing a carboxylic acid having a sulfonic acid metal base together with a polyhydric alcohol and a carboxylic acid that are commonly used in polyester synthesis. In order for this copolyester to have hydroxyl groups at both ends, the polyhydric alcohol component may be synthesized in excess of the total carboxylic acid component including the carboxylic acid having a sulfonic acid metal base.

Examples of the carboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 1,5-naphthalic acid, cono-phosphoric acid, adipic acid, azediic acid,
Sebacic acid, dicarboxylic acids such as aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, p-oxybenzoic acid, p-
Aromatic oxycarboxylic acids such as (2-hydroxyethoxy)benzoic acid can be used, and among these, terephthalic acid, isophthalic acid, adipic acid, sebacic acid, etc. are particularly preferred.

In addition, examples of the polyhydric alcohol which is another component of the copolymerized polyester include ethylene glycol, propylene glycol, 1.3-7"ropanediol, 1.4-butanediol, 1,5-bentanediol, neopentyl glycol, , 6-hexanediol, 2,2.4-) dimethyl-1,6-bentanediol, aliphatic diols or substituted derivatives thereof, cycloaliphatic diols such as 1,4-cyclohexane dimetatool, diethylene glycol, diethylene glycol, Diols such as polyalkylene glycols such as polyethylene glycol, polyglobylene glycol, and polytetramethylene glycol;
Ethylene oxide adduct or propylene oxide adduct to bisphenol, hydrogenated bisphenol A
Oxides such as alkylene oxide adducts of aromatic diols such as ethylene oxide adducts or propylene oxide adducts can be used.

Examples of the carboxylic acid having a sulfonic acid metal group which is another component of the copolymerized polyester include 2-sodium sulfoterephthalic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic acid, and 5-potassium sulfoisophthalic acid. Preferred examples include aromatic dicarboxylic acids containing an alkali metal sulfonate base, but any of the organic acids exemplified as the carboxylic acid component mentioned above that have a metal sulfonate base may be used. I can do it. As the sulfonic acid metal base, it is preferable to use an alkali metal base.

The content of the carboxylic acid component containing these sulfonic acid metal bases is approximately 0.2% based on the total carboxylic acid component.
The range is preferably from 1 mol to 30 mol, preferably from about 0.5 mol to 10 mol. If the carboxylic acid component having such a sulfonic acid metal base is too small, inorganic powders having hydrophilic groups on the surface, such as γ-Fe2
Affinity for magnetic powder such as O3 becomes insufficient. Furthermore, if the amount of the carboxylic acid component having a metal sulfonic acid group is too large, the solubility in the organic solvent used in preparing the paint will be poor.

The triisocyanate compound which is the ω) component of the electron gland curable resin of the present invention includes two isocyanate groups that form a urethane bond through an addition polymerization reaction with the hydroxyl groups at both ends of the above-mentioned copolyester; A compound having one incyanate group in one molecule, which has lower reactivity than two isocyanate groups, is used. Such a triisocyanate compound is represented by the general formula: % formula % (wherein R represents a divalent hydrocarbon residue having 2 or 2 carbon atoms, and 1 represents a side order of 4 or more). Triisocyanate compounds can be used. In this general formula, in order to distinguish between the six incyanate groups, each is conveniently replaced with Y medium Z river/song −=−=・(3).

More specifically, Y and Z have twice the reactivity of X at room temperature, and this difference in reactivity further widens as the temperature increases and as l increases. If l is smaller than 4, this difference in reactivity becomes small, which is not preferable.

The above general formula (after 1 month, the compound in the case of l double is,
2-isocyanatoethyl 2,6-dicyanatohexanoate, 6-isocyanatopropyl 2,6-dicyanatohexanoate, 2,6-dicyanatohexane #
-2-incyanato-2-methylethyl. All of these can be produced by phosgenating an ester of lysine and an amino alcohol.

It is difficult to synthesize a compound in the general formula (1) in which R has 1 carbon atom, and if the number of carbon atoms is 4 or more, the reactivity of incyane) AZ decreases, so it is not suitable.

The υ component of the electrocurable resin of this invention includes an active hydrogen atom that reacts with an isocyanate group to form an intermolecular bond, and a double bond that is cleaved by electron beam irradiation.
A compound having in the molecule is used. This compound has a hydroxyl group and an acrylic or methacrylic double bond at the end of the molecule, and has the general formula: % formula % (4) (wherein, R1 is a hydrogen atom or a methyl group, R2 means an unsubstituted or substituted alkylene group. General formula (
In 4), the alkylene group is a linear or branched divalent saturated hydrocarbon residue having 1 carbon atom.
Preferably, the number is from 1 to 12. This alkylene group is a halogen atom, an alkyloxy group having 1 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, or an alkenyloxy group having 2 to 4 carbon atoms.
may be substituted with a substituent such as an alkenylcarbonyloxy group, and these alkyloxy groups, alk=A/oxy groups, J-,5-yohyalkyanylcarbonyloxy groups may be further substituted with 1 to 6 halogens. May be substituted with an atom.

Among the compounds represented by the general formula (4), preferred examples include acrylic acid or methacrylic acid ('1O)
2-hydroxyethyl ester, 2-hydroxyethyl ester, 2-hydroxybutyl ester, 2-hydroxyoctyl ester, 2-hydroxydodecyl ester, 2-hydroxy-6-chloropropyl ester, 2
-hydroxy-6-acryloxypropyl ester,
2-hydroxy-3-methacryloxypropyl ester, 2-hydroxy-3-acetoxypropyl ester, 2-hydroxy-3-chloroacetoxypropyl ester, 2-hydroxy-6-dichloroacetoxypropyl ester, 2-hydroxy-6- Dolichloroacetoxyglobyl ester, 2-hydroxy-6-chlodonyloxypropylethyl, acrylic or methacrylic double compound having active hydrogen that reacts with 2-hydroxy-6-allyloxyester group. Any monomer having a bond can be applied to the present invention.

The electron beam curable resin of the present invention, which consists of the above-mentioned method, can be synthesized by the following method. First, the copolymerized polyester of component (5) is reacted with the triisocyanate compound of component ω). At this time, the reaction ratio M of the triisocyanate compound to the copolymerized polyester
(molar ratio) is set to 1<M<2 (molar ratio M' of isocyanate groups in the triisocyanate compound to hydroxyl groups in the copolymerized polyester: 1.5<M'<3). When the copolymerized polyester and the triisocyanate compound are subjected to addition polymerization in this manner, the chain length of the copolymerized polyester is two-dimensionally extended by the triisocyanate compound via the urethane bond, and two double bonds are added at both ends. A polyester polyurethane having at least one side chain is obtained. In this case, if a triisocyanate compound in which all three incyanes 14 have the same reactivity is used, the chains of the polyester polyurethane grow three-dimensionally, resulting in gelation, which is disadvantageous both in terms of synthesis and use.

The thus obtained polyester polyurethane is reacted with the compound of component (Q) to introduce a double bond to obtain an electron beam curable resin. This is an addition reaction with atoms, and when the active hydrogen atom is a hydrogen atom in a hydroxyl group, a urethane bond is formed.Also,
This addition reaction is carried out by controlling the reaction conditions as necessary and adding 1 molecule to each end of the polyester polyurethane.
The reaction is carried out so that not only the highly reactive isocyanate groups present, but also the less reactive isocyanate groups present at both ends and side chains participate in the reaction.

In this way, an electron beam curable resin having double bonds at both ends and side chains and having a sulfonic acid metal base is obtained. The molecular weight and number of double bonds of this electron beam cured all resin can be adjusted arbitrarily by selecting the mixing ratio of the copolymerized polyester and the triinocyanate compound. is obtained. Although the molecular weight also depends on the molecular weight of each component (A), CB, and (C), it is preferably in the range of 600 to 50,000.

Table 1 shows copolymerized polyester (molecular weight 2610), triisocyanate compound (T-100, manufactured by Toshikushi 11,
When using molecule M267) and 2-hydroxyethyl methacrylate (molecular weight 160), the blending ratio of the copolymerized polyester and the triisocyanate compound (expressed as the ratio of hydroxyl groups to isocyanate groups) and the ratio of the resulting electron beam curable resin The relationship between the number of double bonds and the molecule tB (number of igc) is shown.

(Continued on next page) Table 1 The electron beam curable resin of the present invention is useful as a binder for paints containing inorganic powders with hydrophilic groups on the surface, especially magnetic paints used in the production of magnetic recording media. It is. That is, since the electron beam curable resin of the present invention has a highly hydrophilic sulfonic acid metal base in its molecule, the sulfonic acid metal base improves the dispersibility of the inorganic powder in the paint. Further, the electron beam curable resin of the present invention has a double bond at both ends and a side chain, and the length of this double bond can be arbitrarily changed. Therefore, even when the molecular weight of the resin is low, the crosslinking density of the coating film after electron beam irradiation can be increased, and the mechanical strength, strength, solvent resistance, etc. of the coating film can be improved.

When the electron beam curable resin according to the present invention is used as a binder for a magnetic recording medium, other materials constituting the magnetic recording medium can be fine powders of commonly used materials. As ferromagnetic iron oxide particles, when expressed as 2FeC)x, the value of
50), magnetite (Fe3O4X-1,33 and their solid solutions (FeOx 1.33 <X< 1.5
0) can be used. Cobalt may be added to these ferromagnetic iron oxides for the purpose of increasing coercive force. There are two types of cobalt-containing magnetic iron oxide: doped type and coated type, and either type may be used. As ferromagnetic chromium dioxide, CrO2 or nu * Sn @Te m Sb e Fe aT is used for the purpose of attaching He to these.
It is possible to use a material to which at least one substance such as isVsMn is added. The ferromagnetic alloy powder is F6. Cos can be used, and Al and S can also be used to improve various properties of these.
There are materials to which metal components such as L, Ti, Cr, Mn, and Cu1Zn are added.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone, methyl imbutyl ketone, and cyclohexanone; methyl acetate, ethyl acetate, butyl acetate, ethyl lactate,
Ester systems such as acetic acid glycol monoethyl ether; Glycol ether systems such as ether, fs:r-ruyl ether, glycol monoethyl ether), Ru, dioxa/etc.; Tar systems such as benzene, toluene, xylene, etc.
(aromatic hydrocarbons); Methylene chloride, ethylene chloride, carbon tetrachloride, chloroform, and ethylene chloride can also be used as abrasives, such as aluminum oxide, chromium oxide, and silicon oxide, as antistatic agents such as carbon black, and as lubricants. Molybdenum disulfide, graphite, silicone oil, olive oil, etc. can also be added.

Further, the binder may be a resin conventionally used as a binder for magnetic recording media together with the electron beam curable resin according to the present invention. In this case, the electron beam curable resin according to the present invention is preferably contained in an amount of 20% by weight or more in the total binder. If this is less than 20% by weight, examples of resins crosslinked by electron beam irradiation include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate- Maleic acid copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, acrylic ester-acrylonitrile copolymer, acrylic ester-vinylidene chloride copolymer, methacrylic ester-vinyritine chloride copolymer Combined, methacrylic acid ester-styrene co-electro^ II-Mountain l-++-Mll Al1-
, e vl top -1h , j feather μ ■ko 呵 -l
Fu ξノ S+ fat, polyvinyl fluoride, vinylidene chloride, acrylonitrile copolymer, butadiene-acrynitrile copolymer, acrylonitrile-butadiene-acrylic acid copolymer, acrylonitrile-butadiene-methacrylic acid copolymer, polyvinyl butyral , cellulose derivatives, styrene/-butadiene copolymers, polyester resins, phenolic resins, epoxy resins, thermosetting polyurethane resins, urea resins, melamine resins, alkyd resins,
Examples include urea-formaldehyde resins and mixtures thereof.

A magnetic paint made of these materials is applied to a non-magnetic carrier according to a conventional method. Materials for this non-magnetic carrier include polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate; polyolefins such as polyethylene and polypyrene; Cellulose derivatives such as pionate; vinyl resins such as polyvinyl chloride and polypinidene chloride; polycarbonate, polyimide,
In addition to plastics such as polyamide-imide, non-magnetic metals such as aluminum, copper, tin, zinc or non-magnetic alloys containing these; ceramics such as glass, earthenware and porcelain; paper, baryta or polyethylene; Papers coated or laminated with α-polyolefins having 2 to 10 carbon atoms such as polypropylene and ethylene-butene copolymers can also be used. These nonmagnetic carriers may be transparent or opaque4 depending on the intended use. Further, the form of the nonmagnetic carrier may be any film, tape, sheet, disk, card, drum, etc., and various materials are selected as necessary depending on the form. The thickness of these nonmagnetic carriers is about 1 to 50 μm, preferably 1 to 60 μm when they are in the form of a film, tape, or sheet. Further, in the case of a disk or card shape, it is about 0.5 to 10 centimeter, and in the case of a drum shape, it is cylindrical, and the shape is determined depending on the recorder used.

After a magnetic paint is applied to a non-magnetic carrier and dried, the paint film is usually calendered and then irradiated with an electron beam to harden it. The irradiation amount of electron beam is about 1~10r=Ira d
about 2-7 Mrad is more desirable.

When using an electron beam accelerator for irradiation, the acceleration voltage is approximately 1
It is preferable to set it to 00KV or more. In addition to electron beams, ionizing radiation such as neutron radiation 1 and gamma rays can also be used.

The present invention will be explained in detail below. Note that all "parts" used herein mean "parts by weight."

Example: Synthesis of electron beam curable resin In a reaction vessel equipped with a thermometer, a stirrer, and a partial reflux condenser, 73 parts of methyl ethyl ketone, 73 parts of toluene, and copolymerized polyester (number average molecule
s Carboxylic acid component: terephthal @ 20 mol, isophthalic acid 15 mol, sodium 5-sulfoisophthalate 5 mol, sebacic acid 60 mol, polyhydric alcohol component: ethylene glycol 50 parts, triisocyanate compound (T- 10
0, made by Toshikaku11)) 5.98 copies, 4 people, one bow, one bow, and a habit of Tochi Kodo! To the mixture was added a porridge, and the mixture was reacted at 70 to 90° C. for 3 hours to produce polyester polyurethane. Next, 2-hydroxyethyl methacrylate ( )I
'F. MA) 3.7 4 parts were added, and the reaction was further carried out at 70 to 90°C for 6 hours to obtain an electron beam curable resin. −
The number average molecular weight of this electron beam curable resin is 18,700,
The number of double bonds in the molecule is 9 (2 Il at each end!,
5 in the side chain).

Comparative Example 1: Synthesis of electron beam curable resin having double bonds only at both ends Methyl ethyl ketone 76
parts, toluene 76 parts, copolymerized polyester (molecules!20
, 500, the composition is the same as in Example 1, with the addition of the bamboo blinds,
React at 70-80°C for 6 hours. Next, I.I.E.M.
A1. 27 parts were added, and the reaction was further carried out at 70 to 90°C for 3 hours. The number average molecular weight of the obtained electron beam curable resin was 21.600, and the number of double bonds in the molecule was 4 (2 at each end).

Comparative Example 2: Synthesis of electron beam curable resin not containing 1 base of gold sulfonate In a reaction vessel similar to that used in Example, 73 parts of methyl ethyl ketone, 76 parts of toluene, and 5 parts of copolymerized polyester were added.
0 parts (molecules! 2,550, carboxylic acid components: 20 moles of telalic acid, 20 moles of isophthalic acid, 60 moles of sebacic acid, polyhydric alcohol components: 50 moles of ethylene glycol, 50 moles of globylene glycol), triisocyanate Compound (T-100) 6.12 Departmenta Gongdu = 1 Daikodosha! ≠ Yohoben Juki was added and the reaction was carried out at 70-90"C for 6 hours. Next, 3.82 parts of I (EMA) was added and the reaction was further carried out at 70-90"C for 3 hours.The obtained electron beam cured The resin had no sulfonic acid metal base, its number average molecular weight was 18,300, and the number of double bonds was 9 (2 at each end and 5 at the side chain).

Using the resins of Examples and Comparative Examples 1 and 2, these were
After drying at 25 mm Hy- for 6 days to form a film of approximately 100 ttm, this film was cured by irradiating 5 Mrad of electron beams at an accelerating voltage of 200 KV.

The obtained cured film has a width of 0.625c1rL and a length of 10cm.
It was cut into a tanzaku shape and its tensile properties were measured using a universal Hibari tester. The results are shown in Table 2.

Table 2 As is clear from Table 2, the molecular weights of the resins in Example and Comparative Example 1 are almost the same, but the resin in Example and Comparative Example 1 has the same breaking strength and Young's modulus when formed into a cured film. is significantly improved.

This is because the resin of the example has a large number of double bonds and also contains double bonds in the side chains, indicating that crosslinking occurs efficiently when irradiated with an electron beam. ing.

Magnetic tapes were produced in the following manner using the resins obtained in the Examples and Comparative Examples described above.

10 parts of γ-Fe203 magnetic particles, 5 parts of methyl ethyl ketone
A mixture of 1 part and 15 parts of toluene was kneaded for 6 hours using a ball mill. A separately prepared mixed solution of 2.5 parts of the resin of Example 1, 5 parts of methyl ethyl ketone and 75 parts of toluene was added to this mixture, and the mixture was heated again using a ball mill for 24 hours.
Kneaded for hours. After defoaming the resulting mixture, it has a thickness of 16
25μm on polyethylene terephthalate film
It was applied using a doctor blade with a gap of m and then placed in a parallel magnetic field of 9000e for about 1 second.

Then, it was left in a hot air dryer at 90° C. for about 60 minutes to remove the solvent, and the thickness of the magnetic coating film was reduced to 8.0 μm.

This R,s (Br/sm) was 0.87.

Separately, a magnetic coating film was formed on a polyethylene terephthalate film by the same method using the resin of Comparative Example 1.2.

Five electron beams were applied to these tapes at an accelerating voltage of 200 KV.
The magnetic coating was cured by Mrad irradiation.

Each of the magnetic tapes obtained in this way was examined in the following manner.

1. Tensile Properties Test The cured magnetic tapes of Example 1 and Comparative Examples 1.2 were cut into a tanzag shape with a width of 0.625 cm and a length of 10 CTL and measured using a universal tension tester.

2. Solvent resistance test The magnetic coating was rubbed with gauze containing methyl ethyl ketone, and the number of times the coating was rubbed until the coating disappeared was expressed as the number of times the coating was rubbed.

6. Powder drop test When the tape is actually run, the amount attached to pinch rollers, capstans, guides, rads, etc. is determined by the point deduction method.
It was displayed as 5 points.

Table 3 shows the test results for each tape.

(Continued on next page.) From Table 6, it can be seen that there is no difference in dispersibility between the magnetic tapes using the resins of Example and Comparative Example 1, but the Young's modulus Ei.

The magnetic tape using the resin of the example is far superior in terms of solvent resistance and powder shedding. This is because the number of double bonds in the molecule is 9 in the example compared to 4 in the comparative example, so the magnetic effect due to electron sand irradiation is not as strong as when comparing the squareness ratio of the example and comparative example 2. it is obvious.

From the above, it can be seen that the electron beam curable resin according to the present invention has excellent coating film properties after electron beam curing, and also improves the dispersibility of the thermal machine object.

Agent Masaru Ueya Yoshio Tsuneko Toshiki Sugiura

Claims (1)

[Scope of Claims] An electron beam curable resin obtained by adding the following component (Q) to a polyester polyurethane comprising the following component and the following component and having isocyanate groups at both ends and side chains. A copolymerized polyester containing 0.2 to 30 mole of carboxylic acid having a metal base based on the total carboxylic acid component and having hydroxyl groups at both ends of the molecule. A triisocyanate compound in which the isocyanate group is less reactive than the other two isocyanate groups. (0, compound having at least one active hydrogen atom and a double bond.