JP2005314627A - Polyurethane resin for coating recoding base material and coating composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin for coating a recording base material and a coating composition for coating a recording base material containing the same. <P>SOLUTION: To provide a polyurethane resin for coating a recording base material which allows jetted ink, not only to infiltrate swiftly into, but also to fix stably on without spreading, various recording materials such as a fiber, paper, synthetic paper, a plastic film, and nonwoven fabric, and particularly improves the recording base material in water resistance and coloring; and a coating composition containing the resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyurethane resin for recording substrate coating and a recording substrate coating composition containing the same, and more specifically, when inkjet printing is performed on various recording substrates such as fibers, paper, synthetic paper, plastic films, and nonwoven fabrics. In addition to the rapid penetration of ink into the base material, the ink can be fixed stably without ink bleeding, and in particular, the polyurethane resin for recording base material coating, which is intended to improve the water resistance and color development of the recording base material. A coating composition comprising:

  In general, the ink jet recording method is a method in which ink is directly jetted onto a recording base material, and the operation cost is lower than that of other conventional recording methods, there is almost no noise, and color recording is easy. Has received a lot of attention. An ink absorbing layer is formed on a base material used for such ink jet recording in order to facilitate ink absorption.

  The ink absorbing layer coated on the surface of the recording substrate is usually formed by coating a composition produced mainly from various pigments and binder resins. At this time, precipitated silica, alumina sol, calcium carbonate, aluminum hydroxide, zeolite, etc. are used as the pigment, and polyvinyl alcohol, starch, casein, carboxymethyl cellulose, hydroxyethyl cellulose, nitrocellulose, polyacrylic acid are used as the binder. Sodium polyacrylate, styrene butadiene latex, polyvinyl acetate emulsion, acrylic emulsion, aqueous urethane emulsion and the like are used.

  For example, JP-A-57-36692 discloses an inkjet recording sheet coated with a basic latex polymer to improve water resistance, resolution, etc., and JP-A-57-82085 discloses. A recording sheet having an ink receiving layer made of a water-soluble resin containing an inorganic pigment and an organic pigment is disclosed. Japanese Patent Laid-Open No. 62-268682 discloses a recording sheet having an ink receiving layer comprising a finely divided silica and a polyvinyl alcohol copolymer having a silanol group. JP-A-62-83178 proposes an ink jet recording sheet having a coating layer containing finely powdered silicic acid and a cationic polymer emulsion.

  However, although the recording substrate coated with the composition comprising the pigment and the resin as described above can improve the fixing property and water resistance of the ink to some extent, if the water resistance is improved, the ink water absorption is decreased. There has been a problem that water resistance and ink water absorption cannot be kept at a high level at the same time.

  In particular, the binder used in the coating composition of the conventional recording substrate is almost water-based. When the film is used as the substrate, it cannot be directly coated because the adhesive strength with the film is weakened. There was a problem that the coating work had to be performed after applying.

Therefore, it has excellent adhesion to various recording substrates including plastic film, including fiber, paper, synthetic paper, and non-woven fabric. In addition, when ink-jet printing is performed, the ink quickly soaks into the substrate and there is no ink bleeding. In particular, a binder and a coating composition that can be fixed on a recording substrate and that can improve the water resistance of the recording substrate have been desired. In response to such a demand, the inventor can use the binder usefully for coating various recording substrates. As a result of extensive research to find a coating composition, the present invention has been completed.
JP 57-36692 A JP 57-82085 A Japanese Patent Laid-Open No. 62-268682 JP 62-83178 A

  Therefore, the present invention is not only excellent in adhesion to the recording substrate when used as a recording substrate coating composition, but also improves the water resistance of the recording substrate and does not use a pigment. In addition, it is an object to provide a polyurethane resin for coating a recording base material that allows ink to permeate quickly only by its own water absorption.

  Another object of the present invention is to provide a method for producing the polyurethane resin.

  Still another object of the present invention is to provide a composition for coating a recording substrate containing the polyurethane resin, which allows ink to permeate quickly and stably fix without ink bleeding.

  Still another object of the present invention is to provide a recording substrate prepared by coating the coating composition.

In order to achieve the above object, the present invention provides a polyurethane resin for coating a recording substrate, which is represented by the following formula 1 in which a hydrophilic part, a lipophilic part and a cationic part coexist.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R ⁴ is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)
The present invention also provides a prepolymer of the following formula 2 by reacting a polyol and a diisocyanate in the presence of a catalyst in order to effectively produce a polyurethane resin represented by the formula 1, A solvent and a diol chain extender are added to produce a compound of formula 3 through a primary chain extension reaction, a diamine chain extender is added to the compound of formula 3 again, and a urethane polymer of formula 4 is converted through a secondary chain extension reaction. There is provided a method for producing a polyurethane resin for coating a recording substrate, characterized by comprising producing and reacting a urethane polymer of formula 4 with a cationizing agent.

(In the formula, R, R ¹ and m are the same as defined in Formula 1.)

(In the formula, R, R ¹ , R ² , m and k are the same as defined in Formula 1.)

(In the formula, R, R ¹ , R ² , R ³ , m and k are the same as defined in Formula 1.)
The present invention also provides a composition for coating a recording substrate, which is produced by the above production method and contains a polyurethane resin having a solid content of 10 to 30%.

  The present invention also provides a recording base material obtained by coating the base material with the above coating composition.

  As described above, the present invention can not only soak ink quickly into the substrate but also stably fix it without ink bleeding when printing on various recording substrates such as fiber, paper, synthetic paper, plastic film, and non-woven fabric. In particular, there is a useful effect that can provide a polyurethane resin for coating a recording substrate and a coating composition containing the same, which are designed to improve the water resistance and color development of the recording substrate.

  Hereinafter, the present invention will be described in more detail.

  The polyurethane resin used as a binder in the composition for coating an ink jet recording substrate according to the present invention is represented by the following formula 1 in which a hydrophilic part, a lipophilic part and an ionic part coexist.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R 4 is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)
In the above formula 1, R is a portion obtained by removing the NCO group from the diisocyanate compound, and the same diisocyanate compound as that used in the production of a normal polyurethane resin can be applied. The diisocyanate compound applied in the present invention is 2 , 4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, 4,4-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,4-cyclohexyl diisocyanate, 4,4-dicyclohexylmethane diisocyanate, 4,6 -Xylene diisocyanate, 3,3'-dimethyl-4,4'-phenylene diisocyanate, 3,3'-dichloro-4,4 'bisphenylene diisocyanate, isophorone diisocyanate, xylene diisocyanate Are those selected from the group consisting of 1,6-hexamethylene diisocyanate.

In Formula 1, R ¹ is a portion obtained by removing an OH group from a polyol compound, and the polyol compound is a polyether polyol selected from polyethylene glycol and polypropylene glycol, a polyester polyol, a polycarbonate polyol, and ethylene glycol and propylene. It is selected from block copolymerized polyols with glycols. At this time, any polyol compound preferably has a high degree of polymerization having a molecular weight of 2000 to 12000.

More preferably, R ¹ is expressed by the following formula 5 derived from polyethylene glycol among the polyol compounds.

(In the formula, n is an integer of 50 to 250.)
In the above formula 1, R ² is a portion excluding the OH group of the diol chain extender, and the diol chain extender is ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, It is selected from tetramethylene glycol and N-methyldiethanolamine.

More preferably, R ² is expressed by the following formula 6 derived from N-methyldiethanolamine among diol chain extenders.

(In the formula, R ⁴ is the same as defined in Formula 1 above.)
In the above formula 1, R ³ is a portion excluding the NH ₂ group of the diamine chain extender, and the diamine chain extender is ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylenediamine, diamino. It is selected from diphenylmethane, isophoronediamine, piperazine, diaminocyclohexylmethane, and 2-methylpiperazine.

In the above formula 1, R ⁴ is a cation moiety derived from a cationizing agent, and the cationizing agent is selected from dimethyl sulfonate, acetic acid, phosphoric acid, hydrochloric acid, and sulfuric acid.

  Next, the polyurethane resin having the structure of the above formula 1 will be described in more detail through a manufacturing method thereof.

  The polyurethane resin having the structure of the above formula 1 is prepared by reacting a polyol and a diisocyanate in the presence of a catalyst to produce a prepolymer of the following formula 2, and adding an organic solvent and a diol chain extender to the produced prepolymer. Then, a compound of formula 3 is produced through a primary chain extension reaction, a diamine chain extender is added to the compound of formula 3 again, and a urethane polymer of formula 4 is produced through a secondary chain extension reaction. It can be easily obtained by adding a cationizing agent and then reacting.

(In the formula, R is a portion obtained by removing an NCO group from a diisocyanate compound, R ¹ is a portion obtained by removing an OH group from a polyol compound, and m is an integer of 1 or more.)

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , M and k are integers of 1 or more.)

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH 2 group of the diamine chain extender, and m and k are integers of 1 or more.)

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R ⁴ is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)
At this time, in order to produce the prepolymer of the above formula 2, the NCO group of the diisocyanate is reacted at 3 equivalents or more, more preferably 5 to 7 equivalents with respect to 1 equivalent of the OH groups of the polyol compound. This reaction process is shown in Reaction Formula 1.

(In the formula, R is a portion obtained by removing an NCO group from a diisocyanate compound, R ¹ is a portion obtained by removing an OH group from a polyol compound, and m is an integer of 1 or more.)
At this time, the excess NCO group of the diisocyanate remaining due to the reaction between the polyol and the diisocyanate is used for the reaction of the diol chain extender and the diamine chain extender described later. If there is no further change in the NCO group content during the reaction process, the reaction is considered to have been completed and the process proceeds to the next reaction. The content of the NCO group can be easily confirmed by applying a usual method of reacting with di-N-butylamine and adjusting unreacted di-N-butylamine with hydrochloric acid.

  The isocyanate compound used for producing the prepolymer can be the same as that used in the usual polyurethane resin production. For example, the diisocyanate compound is 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5. -Naphthalene diisocyanate, 4,4-diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,4-cyclohexyl diisocyanate, 4,4-dicyclohexylmethane diisocyanate, 4,6-xylene diisocyanate, 3,3'-dimethyl-4,4'- Selected from phenylene diisocyanate, 3,3′-dichloro-4,4′bisphenylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, 1,6-hexamethylene diisocyanate It can be used.

  The polyol that reacts with diisocyanate to form a urethane bond is selected from polyethylene glycol and polypropylene glycol selected from polypropylene glycol, polyester polyol, polycarbonate polyol, and block copolymer polyol of ethylene glycol and propylene glycol. These preferred average molecular weights are 2000-12000.

  It is preferable to use polyethylene glycol having an average molecular weight of 2000 to 12000 as the polyol compound, and it is particularly preferable that it has a molecular weight of 4000 to 6000.

  When polyethylene glycol having a polymerization degree in such a range is used as a polyol compound, a large amount of a lipophilic part due to urethane bond and a hydrophilic part of ethylene oxide group are secured in the produced polyurethane resin. When the film is coated with a polyurethane resin containing a large amount of the hydrophilic part, the adhesion is increased, so that it can be coated without a separate primer coating operation.

  The reaction between the diisocyanate and the polyol is carried out in the presence of a catalyst. The catalyst used in the usual polyurethane resin production is preferably used within the range of the usual addition amount. Examples of catalysts that can be used include those selected from dibutyltin dilaurate, stannous octate, and dibutyltin mercaptide.

  When the polyol and diisocyanate are reacted in the catalyst in this way, the prepolymer of Formula 2 can be produced, and if there is no further change in the content of NCO groups in the reaction process, the reaction is considered to be completed and the next reaction proceeds.

  When the reaction is completed, the compound of formula 3 is produced by reacting the prepolymer of formula 2 with the diol chain extender as shown in the following reaction formula 2 in an organic solvent. At this time, the NCO of the prepolymer of formula 2 is prepared. The reaction is carried out at a ratio of 0.3 to 0.8 equivalent of OH group of the diol chain extender to 1 equivalent of the group.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , M and k are integers of 1 or more.)
At this time, when the reaction equivalent of the diol chain extender is less than 0.3 equivalent with respect to 1 equivalent of the NCO group of the compound of formula 2, the chain of the finally produced polyurethane compound becomes long. Polyurethane compound finally produced when the reaction equivalent of the diol chain extender exceeds 0.8 equivalent, while there is a drawback that the part that changes to cationic property is reduced and the fixing property of the ink is remarkably inferior. As the chain length becomes shorter, the number of parts that change to cationicity increases, and the ink fixing property is improved.However, since the lipophilic part is relatively reduced, the adhesion to the recording substrate deteriorates. is there. Therefore, it is preferable to use a diol chain extender within the above range.

  As the diol chain extender, one selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, tetramethylene glycol, and N-methyldiethanolamine can be used.

  Preferably, N-methyldiethanolamine is used as the diol chain extender. When N-methyldiethanolamine is used as the chain extender in this way, the nitrogen portion exhibits cationicity when the cationizing agent is added at the same time as the chain extension. Therefore, an ionic moiety is present in the molecular structure of the polyurethane resin according to the present invention. Will become more increased.

  As described above, after reacting with the prepolymer of Formula 2 using a diol chain extender, if there is no further change in the content of NCO groups in the reaction process, the reaction is considered to be completed and the next reaction is performed. move on.

  The organic solvent used for the reaction can be selected from toluene, methyl ethyl ketone, N, N-dimethylformamide, tetrahydrofuran, isopropyl alcohol, etc., and the solid content of the polyurethane resin produced according to the amount of the organic solvent Since it can be adjusted, it is recommended to use it with appropriate adjustment. In particular, if necessary, the produced polyurethane resin may be diluted with an organic solvent.

When the reaction is completed, a urethane polymer of formula 4 is produced by adding and reacting a diamine chain extender to the compound of formula 3 as shown in the following reaction formula 3. At this time, the NH ₂ group of the diamine chain extender is reacted at an equivalent ratio of 1.01 to 1.10 with respect to 1 equivalent of the NCO group of the compound of Formula 3.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, and m and k are integers of 1 or more.)
At this time, the diamine chain extender reacts with the NCO groups at both ends of the compound of Formula 3 to change both ends of the compound to amine groups (NH ₂ ) and thicken the same as in Formula 4. Add to. The post-reaction viscosity is approximately 1000-15000 CPS at 25 ° C.

  When the diamine chain extender is added and reacted in this way, the chain is extended while the urea bond is formed, whereby the manufactured polyurethane resin has water resistance and water resistance in addition to ensuring hydrophilicity by the urea bond. Yellowing and durability are improved.

  The diamine chain extender should be selected from ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylenediamine, diaminodiphenylmethane, isophoronediamine, piperazine, diaminocyclohexylmethane, and 2-methylpiperazine. Can do.

  Thus, after making it react with the compound of Formula 3 using a diamine type | system | group chain extender, when NCO content does not appear any more, it will consider that reaction was completed and will progress to the next reaction.

  When the reaction is completed, as shown in the following reaction formula 4, a cationizing agent is added to the urethane polymer of formula 4 and reacted to obtain a polyurethane resin of formula 1. At this time, the cationizing agent is added and reacted at a ratio of 1 to 1.2 equivalents per 1 equivalent of the amine group of the compound of formula 3.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R ⁴ is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)
As described above, when a cationizing agent is added to the urethane polymer of Formula 4, the tertiary amine moiety in the molecule becomes cationic while changing to a quaternary amine. When the primary amine is formed, the ink is fixed while ion-bonding with most of the ink which is an anion, and as a result, bleeding and dropping of the ink are prevented. As the cationizing agent, one selected from dimethyl sulfonate, acetic acid, phosphoric acid, hydrochloric acid, and sulfuric acid can be used.

  The polyurethane resin produced by such a method has an average molecular weight of 10,000 to 100,000 g / mol, and exhibits unique physical properties since a hydrophilic part, a lipophilic part and a cationic part coexist in one molecule. In particular, the water absorption by the hydrophilic part and the durability by the oleophilic part are improved, and the fixing property of the ink by the cationic part is greatly improved.

  Therefore, the polyurethane resin produced by the above-described method can be usefully used for the coating composition for an inkjet recording substrate. According to the present invention, the recording comprising the polyurethane resin produced by the above-described method of the present invention. Substrate coating compositions can be provided.

  At this time, the urethane resin can be fluidly added within the content range of the resin used in a normal coating composition for an inkjet recording substrate. In the present invention, the urethane resin is based on 100% by weight of the total coating composition. 20 to 60% by weight and the remaining amount was an organic solvent.

  As described above, the urethane resin according to the present invention provides excellent ink water absorption and fixability without using a separate pigment. This is because the hydrophilic part, the lipophilic part and the cationic part coexist in the molecule of the urethane resin according to the present invention as described above.

  If necessary, the recording substrate coating composition of the present invention may further contain various additives such as pigments, ultraviolet absorbers or ultraviolet stabilizers used in ordinary inkjet recording substrate coating compositions. .

  As the pigment, those used for a general recording substrate coating composition can be applied, and it is preferable to use a pigment selected from silica powder, alumina powder, titanium dioxide powder or colored pigment powder.

  In addition, if the composition further contains a UV absorber or UV stabilizer, it is possible to prevent the polyurethane resin from being decomposed by UV light, thus improving the long-term storage properties of the recording substrate coated with the coating composition. The UV absorbers and UV stabilizers should be selected from those commonly used.

  Examples of UV absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, pt-butyl salicylate, phenyl salicylate, 2,4-dihydroxybenzophenone and the like, and examples of UV stabilizers include nickel bis (octylphenyl) sulfate, nickel dibutyldithiocarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, etc. There is.

  The recording substrate coating composition having the above-described composition can be coated on various ink jet recording substrates, and various recording substrates including paper, fiber, synthetic paper, plastic film, non-woven fabric, etc. are used. it can.

  When such a recording substrate is coated with the coating composition according to the present invention, when ink-jet printing is performed, the ink quickly soaks into the substrate, and the ink can be stably fixed without ink bleeding. Color development is improved.

Hereinafter, the present invention will be described in more detail on the basis of the following examples. However, these examples are merely presented to help the understanding of the present invention, and the present invention is not limited thereto.
<Example 1>
Manufacture of polyurethane resin After adding 75 g of polyethylene glycol having an average molecular weight of 6000, 16.5 g of isophorone diisocyanate and 0.05 g of dibutyltin dilaurate to a four-flask, the mixture was reacted at 90 ° C. for 3 hours until NCO group content was not changed. A prepolymer containing 5.7% by weight was produced. 109.2 g of DMF and 2.975 g of N-methyldiethanolamine were added thereto and reacted at 60 ° C. for 2 hours until there was no change in NCO group content. 109.2 g of DMF was added again here and 6.375 g of isophoronediamine was added at 60 ° C. After the dropwise addition, it was diluted with 72.8 g of DMF and 72.8 g of toluene. 7.5 g of acetic acid as a cationizing agent was added thereto at 40 ° C. and reacted for 1 hour, and then a polyurethane resin having a final solid content of 20% was produced.
<Example 2>
Production of polyurethane resin NCO group content by adding 52.0 g of polyethylene glycol having an average molecular weight of 4000, 20.44 g of 4,4-dicyclohexylmethane diisocyanate and 0.05 g of dibutyltin dilaurate to a four-necked flask, followed by reaction at 90 ° C. for 3 hours. A prepolymer containing 7.54% by weight of NCO groups was produced until no change. To this, 102.72 g of DMF and 3.09 g of N-methyldiethanolamine were added and reacted at 60 ° C. for 2 hours until the NCO group content did not change. Then, 102.72 g of DMF was added again, and diethyltoluenediamine was added at 60 ° C. After 953 g was added dropwise, it was diluted with 68.48 g of DMF and 68.48 g of toluene. 7.8 g acetic acid as a cationizing agent was added thereto at 40 ° C. and reacted for 1 hour, and then a polyurethane resin having a final solid content of 20% was produced.
<Example 3>
Production of polyurethane resin Into a four flask, 75.0 g of polyethylene glycol having an average molecular weight of 6000, 2.975 g of N-methyldiethanolamine, 16.5 g of isophorone diisocyanate and 0.05 g of dibutyltin dilaurate were added and reacted at 90 ° C. for 3 hours. A prepolymer containing 3.3% by weight of NCO groups was produced until there was no change in the NCO group content. To this was added 109.2 g of DMF, and 6.375 g of isophoronediamine was added dropwise at 60 ° C., and then diluted with 72.8 g of DMF and 72.8 g of toluene. 7.5 g of acetic acid as a cationizing agent was added thereto at 40 ° C. and reacted for 1 hour, and then a polyurethane resin having a final solid content of 20% was produced.
<Example 4>
Production of polyurethane resin In a four-flask, 78.0 g of polyethylene glycol having an average molecular weight of 6000, 5.77 g of isophorone diisocyanate and 0.05 g of dibutyltin dilaurate were placed and reacted at 90 ° C. for 3 hours until the NCO group content did not change. Produced a prepolymer containing 1.303 wt. DMF105.03g and N-methyldiethanolamine 1.547g were added here, and it was made to react at 60 degreeC, DMF105.03g was added, isophorone diamine 2.21g was added dropwise, Then, it diluted with 70.02g of DMF and 70.02g of toluene. . 4.68 g of acetic acid as a cationizing agent was added thereto at 40 ° C. and reacted for 1 hour, and then a polyurethane resin having a final solid content of 20% was produced.
<Example 5>
Production of polyurethane resin In a four flask, 45 g of polyethylene glycol having an average molecular weight of 6000, 10 g of polycarbonate having an average molecular weight of 2000, 2.975 g of N-methyldiethanolamine, 16.5 g of isophorone diisocyanate and 0.05 g of dibutyltin dilaurate were reacted at 90 ° C. for 3 hours. Thus, a prepolymer containing 4.17% by weight of NCO groups was produced until there was no change in the NCO content. To this was added 109.2 g of DMF, and 6.375 g of isophoronediamine was added dropwise at 60 ° C., and then diluted with 72.8 g of DMF and 72.8 g of toluene. 7.5 g of acetic acid as a cationizing agent was added thereto at 40 ° C. and reacted for 1 hour, and then a polyurethane resin having a final solid content of 20% was produced.
<Example 6>
Production of Coating Composition A recording substrate coating composition was produced by mixing 100 g of a mixed solvent with 100 g of a polyurethane resin having a solid content of 20% produced in Example 1 above. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Example 7>
Production of Coating Composition A recording substrate coating composition was produced by mixing 100 g of a mixed solvent with 100 g of a polyurethane resin having a solid content of 20% produced in Example 2 above. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Example 8>
Production of Coating Composition A recording substrate coating composition was produced by mixing 100 g of a mixed solvent with 100 g of a polyurethane resin having a solid content of 20% produced in Example 3 above. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Example 9>
Production of Coating Composition A recording substrate coating composition was produced by mixing 100 g of a mixed solvent with 100 g of a polyurethane resin having a solid content of 20% produced in Example 4 above. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Example 10>
Production of Coating Composition A recording substrate coating composition was produced by mixing 100 g of a mixed solvent with 100 g of a polyurethane resin having a solid content of 20% produced in Example 5 above. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Example 11>
100 g of a mixed solvent and 20 g of silica powder were mixed with 100 g of a polyurethane resin having a solid content of 20% produced in Example 1 to prepare a recording substrate coating composition. At this time, the mixed solvent used was a mixture of methyl ethyl ketone, toluene and dimethylformamide in a ratio of 3: 2: 5.
<Experimental Examples 1 to 5>
A front print coating type ink jet recording substrate is prepared by applying the coating composition prepared in Examples 6 to 10 to a PET film so as to have a thickness of 0.3 mm. Obtained. The recording substrate thus obtained was measured for water resistance, ink bleeding, adhesiveness, ink absorption rate, and surface gloss as described below, and the results are shown in Table 1 below.

-Water resistance-
Print black, blue-green, purple, and yellow colors on the recording substrate using an ink jet printer (Epson 830), leave it for 1 hour, and then immerse it in running water for 5 hours to see the changes in the printed part with the naked eye. Observed and evaluated as follows.
○: There is no bleeding in the printed part.
Δ: The printed portion is slightly blurred.
X: A lot of printed portions are blurred.

-Ink bleeding-
A black dot was printed on the recording substrate using an ink jet printer (EPSON 830), and the dot-printed portion was observed by magnifying 50 times with a magnifying glass, and evaluated as follows.
○: No bleeding.
Δ: Slightly blurred.
X: Many blurs.

-Adhesiveness-
The adhesion was measured on the surface of the recording substrate using an adhesion tester (AGS-J / AHIMADZU), and the results were classified into ○ (good), Δ (normal), and × (poor).

-Ink absorption speed-
Print black on the recording substrate using an inkjet printer (Epson 830), rub it with gauze and observe the degree of search hue with the naked eye, and the results are ○ (good), △ (normal), × (bad) It was divided into.

-Surface glossiness-
Black was printed on the recording substrate using an inkjet printer (Epson 830), and the glossiness of the surface was observed with the naked eye, and the results were classified into ○ (good), Δ (normal), and × (poor).
<Experimental example 6>
The coating composition prepared in Example 6 is spot-coated on a PET film to a thickness of 0.3 mm, and the coating composition manufactured in Example 11 is further coated on the PET film to a thickness of 0.3 mm. Then, a second base coating was performed to obtain a recording substrate for inkjet printing on the back side (BACK-LIT TYPE). The recording substrate thus obtained was measured for water resistance, ink bleeding, adhesiveness, ink absorption rate, and surface gloss as in the above experimental examples, and the results are shown in Table 1 below. It was.
<Experimental example 7>
The coating composition produced in Example 6 above was spot coated on a nylon fabric to a thickness of 0.3 mm to obtain a recording substrate for front print coating type inkjet. The recording substrate thus obtained was measured for water resistance, ink bleeding, adhesiveness, ink absorption speed, and surface gloss as in the above experimental examples, and the results are shown in the following table. It was shown in 1.
<Comparative Experiment Example 1>
A known inkjet coating composition comprising 100 g of an acrylic resin having a solid content of 40%, a molecular weight of 2000 to 3000, 100 g of PVA, and 20 g of silica is spot-coated on a PET film to a thickness of 0.3 mm for front printing (front print coating type) A recording substrate for inkjet was obtained. The recording substrate thus obtained was measured for water resistance, ink bleeding, adhesiveness, ink absorption speed, and surface gloss as in the above experimental examples, and the results are shown in the following table. It was shown in 1.

  As shown in Table 1 above, in the case of Experimental Examples 1 to 6 coated on a PET film using the coating composition produced using the polyurethane resin produced according to the present invention, the water resistance, bleeding property, adhesion It can be confirmed that it is very superior to Comparative Experimental Example 1 in which a substrate is coated with a coating composition that has been generally used in terms of properties, absorption speed, glossiness, and the like. Further, in Experimental Example 7 where the base material was used as a fabric, it was found that the water resistance, bleeding property, adhesiveness, absorption speed, and glossiness were very excellent.

Claims (23)

A polyurethane resin for coating a recording substrate, which is represented by the following formula 1, wherein a hydrophilic part, a lipophilic part and an ionic part coexist.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R ⁴ is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)   2. The polyol compound according to claim 1, wherein the polyol compound is selected from a polyether polyol selected from polyethylene glycol and polypropylene glycol, a polyester polyol, a polycarbonate polyol, and a block copolymer polyol of ethylene glycol and propylene glycol. The polyurethane resin for recording substrate coating as described. 3. The polyurethane resin for coating a recording substrate according to claim 1, wherein R ^{1 in} the formula 1 is represented by the following formula 5 derived from polyethylene glycol as a polyol compound.

(In the formula, n is 50 to 250.)   The diol chain extender is selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, tetramethylene glycol, and N-methyldiethanolamine. 2. Polyurethane resin for recording substrate coating described in 1. 5. The polyurethane resin for coating a recording substrate according to claim 1, wherein R ^{2 in} the formula 1 is represented by the following formula 6 derived from N-methyldiethanolamine as a diol chain extender.

(Wherein R ⁴ is the cation moiety of the cationizing agent.)   The diamine chain extender is selected from ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylenediamine, diaminodiphenylmethane, isophoronediamine, piperazine, diaminocyclohexylmethane, and 2-methylpiperazine. The polyurethane resin for recording substrate coating according to claim 5.   7. The polyurethane resin for coating a recording substrate according to claim 6, wherein the cationizing agent is selected from dimethyl sulfonate, acetic acid, phosphoric acid, hydrochloric acid and sulfuric acid. 4. The polyurethane resin for coating a recording substrate according to claim 3, wherein R ^{2 in} Formula 1 is represented by the following Formula 6 derived from N-methyldiethanolamine as a diol chain extender.

(Wherein R ⁴ is the cation moiety of the cationizing agent.) A polyol and diisocyanate are reacted in the presence of a catalyst to produce a prepolymer of formula 2 below, an organic solvent and a diol chain extender are added to the prepared prepolymer, and a compound of formula 3 is converted through a primary chain extension reaction. Then, a diamine chain extender is added to the compound of formula 3 again to produce a urethane polymer of formula 4 through a secondary chain extension reaction, and a cationizing agent is added to the urethane polymer of formula 4 to react with it. A method for producing a polyurethane resin for coating a recording substrate, comprising obtaining a polyurethane resin.

(In the formula, R is a portion obtained by removing the NCO group from the diisocyanate compound, R ¹ is a portion obtained by removing the OH group from the polyol compound, and R ² is a portion obtained by removing the OH group of the diol chain extender. , R ³ is a portion excluding the NH ₂ group of the diamine chain extender, R ⁴ is a cation portion derived from a cationizing agent, and m and k are integers of 1 or more.)

(In the formula, R, R ¹ and m are the same as defined in Formula 1.)

(In the formula, R, R ¹ , R ² , m and k are the same as defined in Formula 1.)

(In the formula, R, R ¹ , R ² , R ³ , m and k are the same as defined in Formula 1.)   10. The recording substrate coating according to claim 9, wherein the NCO group of the diisocyanate is reacted at a 5-7 equivalent ratio with respect to 1 equivalent of the OH group of the polyol compound in order to produce the prepolymer of the above formula 2. For producing a polyurethane resin for use.   As the polyol compound, a polyol selected from polyethylene glycol and polypropylene glycol having an average molecular weight of 200 to 12000, polyester polyol, polycarbonate polyol, and block copolymer polyol of ethylene glycol and propylene glycol are used. The method for producing a polyurethane resin for coating a recording substrate according to claim 9 or 10.   12. The method for producing a polyurethane resin for coating a recording substrate according to claim 11, wherein polyethylene glycol having a molecular weight of 4000 to 6000 is used for the polyol compound.   In order to produce the compound of the above formula 3, the reaction is carried out with the OH group of the diol chain extender in a 0.3 to 0.8 equivalent ratio with respect to 1 equivalent of the NCO group of the prepolymer of the formula 2. A method for producing a polyurethane resin for recording substrate coating according to claim 9.   The diol chain extender is selected from ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, tetramethylene glycol, and N-methyldiethanolamine. 14. A method for producing a polyurethane resin for coating a recording substrate according to 13.   15. The method for producing a polyurethane resin for coating a recording substrate according to claim 14, wherein N-methyldiethanolamine is used as the diol chain extender. In order to produce the compound of the above formula 4, the NH ₂ group of the diamine chain extender is reacted at an equivalent ratio of 1 to 1.2 with respect to 1 equivalent of the NCO group of the compound of the formula 3. The manufacturing method of the polyurethane resin for recording base material coatings of Claim 9.   The diamine chain extender is selected from ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylenediamine, diaminodiphenylmethane, isophoronediamine, piperazine, diaminocyclohexylmethane, and 2-methylpiperazine. The method for producing a polyurethane resin for coating a recording substrate according to claim 16.   10. The method for producing a polyurethane resin for coating a recording substrate according to claim 9, wherein the cationizing agent is selected from dimethyl sulfonate, acetic acid, phosphoric acid, hydrochloric acid, and sulfuric acid.   A recording substrate coating composition comprising a polyurethane resin produced by the production method of claim 9.   20. The recording substrate coating composition according to claim 19, wherein the polyurethane resin is contained in an amount of 20 to 60% by weight based on 100% by weight of the total composition.   21. The recording substrate coating composition according to claim 20, wherein the composition contains 2 to 15% by weight of a pigment.   The composition for coating a recording substrate according to any one of claims 19 to 21, wherein the composition further comprises an ultraviolet absorber or an ultraviolet stabilizer.   A recording substrate produced by coating the substrate with the coating composition of claim 19.