KR20230105701A - Method of manufacturing scratch-resistant coating agent for biaxially oriented polypropylene film - Google Patents

Abstract

The present invention relates to a method for manufacturing a scratch-resistant coating for a biaxially stretched polypropylene film, comprising the steps of dissolving polyol, glycol, and solvent into a reactor and dissolving the polyol and glycol in the solvent by stirring; a prepolymer formation step of forming a prepolymer having an isocyanate group (-NCO) molecular weight of 3.4 to 4.6% by adding diisocyanate to the solvent in which the polyol and the glycol are dissolved; Primary chain extension to form a polyurethane prepolymer having an isocyanate group (-NCO) having a molecular weight of 0.4 to 1.6% at the end by adding a chain extender to the prepolymer to extend the chain including the polyol and the diisocyanate step; Adding silicone diol to the polyurethane prepolymer and extending the chain to obtain a water-dispersed polyurethane resin containing silicone diol and a secondary chain extension step; And an additive addition step of forming a water-dispersion polyurethane coating agent by adding additives such as a curing agent, a thickener, a dispersing agent, a leveling agent, and an antifoaming agent to the water-dispersion polyurethane resin containing the silicone. Accordingly, when water-dispersed polyurethane containing silicone diol is prepared and applied to a coating agent to increase scratch resistance, the effect of improving the scratch resistance of the biaxially stretched polypropylene film to which the coating agent is applied can be obtained.

Description

Method of manufacturing scratch-resistant coating agent for biaxially oriented polypropylene film}

The present invention relates to a method for manufacturing a scratch-resistant coating agent for a biaxially stretched polypropylene film, and more particularly, to a biaxially stretched polypropylene film in which a water-dispersed polyurethane containing silicon diol is prepared and applied to the coating agent to increase scratch resistance. It relates to a method for producing a scratch-resistant coating agent for use.

Biaxially oriented polypropylene film (BOPP film) corresponds to a film whose physical properties are further improved through the biaxially oriented process on the excellent physical properties of polypropylene itself. It corresponds to a plastic film widely used as industrial tapes and coating materials for various printed materials. Such a BOPP film may be specially treated to impart heat sealability, rigidity, printability, scratch resistance, etc., or a special function may be imparted by adding a composition other than polypropylene material.

Common methods for imparting special functions to the BOPP film include post-processing such as coating and deposition on the BOPP film or a method of adding a functional composition when manufacturing the BOPP film. However, the method of adding a functional composition when manufacturing a BOPP film is not appropriate because there are cases in which the biaxial stretching properties of the BOPP film are negatively affected.

In particular, in order to increase the scratch resistance of the surface of the BOPP film, it is preferable to laminate a coating agent having excellent scratch resistance on the surface of the BOPP film so as to impart scratch resistance to the surface while protecting the biaxially stretched property of the BOPP film. Therefore, it is necessary to develop a coating agent having excellent scratch resistance for such a biaxially stretched polypropylene film.

Utility model registration at the Korean Intellectual Property Office No. 20-0373774

The present invention has been made to solve the above problems, and a method for producing a scratch-resistant coating agent for a biaxially stretched polypropylene film in which water-dispersed polyurethane containing silicon diol is prepared and applied to the coating agent to increase scratch resistance. is to provide

The above object is a polyol dissolving step of dissolving the polyol and glycol in the solvent by stirring after putting the polyol, glycol and solvent into the reactor; a prepolymer formation step of forming a prepolymer having an isocyanate group (-NCO) molecular weight of 3.4 to 4.6% by adding diisocyanate to the solvent in which the polyol and the glycol are dissolved; Primary chain extension to form a polyurethane prepolymer having an isocyanate group (-NCO) having a molecular weight of 0.4 to 1.6% at the end by adding a chain extender to the prepolymer to extend the chain including the polyol and the diisocyanate step; Adding silicone diol to the polyurethane prepolymer and extending the chain to obtain a water-dispersed polyurethane resin containing silicone diol and a secondary chain extension step; and an additive addition step of forming a water-dispersible polyurethane coating agent by adding a curing agent, a thickener, a dispersing agent, a leveling agent, and an antifoaming agent to the water-dispersible polyurethane resin containing silicone. It is achieved by a scratch-resistant coating agent manufacturing method for a film.

Here, the silicone diol is preferably one of the following formula (1) or formula (2).

<Formula 1>

<Formula 2>

In addition, 3 to 5 parts by weight of the curing agent, 0.1 to 1 part by weight of the thickener, 1 to 2 parts by weight of the dispersing agent, 0.2 to 0.5 parts by weight of the leveling agent, and 1 to 5 parts by weight of the antifoaming agent are added. desirable.

As described above, according to the present invention, when water-dispersed polyurethane containing silicone diol is prepared and applied to a coating agent to increase scratch resistance, the scratch resistance of the biaxially stretched polypropylene film to which the coating agent is applied is excellent. cancellation effect can be obtained.

1 is a flow chart of a method for manufacturing a scratch-resistant coating agent for a biaxially stretched polypropylene film according to an embodiment of the present invention;
Figure 2 is a photograph comparing the matte effect according to the particle size of polyurethane,
3 is an FT-IR spectrum of the water-dispersed polyurethane resin prepared in Example 1,
Figure 4 is a graph showing the mechanical properties of the water-dispersed polyurethane resin,
5 is a differential scanning calorimeter measurement graph of a water-dispersed polyurethane resin,
6 is a thermogravimetric analysis graph of a water-dispersed polyurethane resin,
7 is a density measurement graph of a water-dispersed polyurethane resin,
8 is a photograph of light transmittance comparison of the water-dispersed polyurethane resin prepared in Example 2,
9 is a photograph evaluating the pencil hardness of the water-dispersible polyurethane resin prepared in Example 3.

Hereinafter, the technical idea of the present invention will be described in more detail using the accompanying drawings. Since the accompanying drawings are only examples shown to explain the technical idea of the present invention in more detail, the technical idea of the present invention is not limited to the form of the accompanying drawings.

1 is a flow chart of a method for manufacturing a scratch-resistant coating agent for a biaxially stretched polypropylene film according to an embodiment of the present invention, FIG. 2 is a photograph comparing matte effect according to the particle size of polyurethane, and FIG. 3 is Example 1 FT-IR spectrum of the water-dispersed polyurethane resin prepared through, Figure 4 is a graph showing the mechanical properties of the water-dispersed polyurethane resin, Figure 5 is a differential scanning calorimeter measurement graph of the water-dispersed polyurethane resin, Figure 6 is a thermogravimetric analysis graph of a water-dispersed polyurethane resin, FIG. 7 is a density measurement graph of a water-dispersed polyurethane resin, and FIG. 8 is a photograph of light transmittance comparison of the water-dispersed polyurethane resin prepared in Example 2, 9 is a photograph evaluating the pencil hardness of the water-dispersible polyurethane resin prepared in Example 3.

The method for manufacturing a scratch-resistant coating for a biaxially oriented polypropylene film (BOPP film) according to the present invention, as shown in FIG. 1, includes a polyol dissolution step (S100), a prepolymer formation step (S200), and It includes a chain extension step (S300), silicon diol addition and secondary chain extension step (S400), and an additive addition step (S500).

First, the polyol dissolving step (S100) means a step of dissolving the polyol in the solvent by stirring after putting the polyol, glycol, and solvent into a reactor.

Polyols used in the production of water-dispersed polyurethane resins are polyether polyols, polyester polyols, polycarbonate polyols, polyacryl polyols, and mixtures thereof. It is preferably selected from the group consisting of This polyol uses a molecular weight of 2,000Mw. If the molecular weight is less than 2,000Mw, the final coating agent is not flexible and is not suitable for application to the BOPP film. If it exceeds 2,000Mw, excellent scratch resistance cannot be obtained. .

Glycol added with polyol is ethylene glycol, 1,4-butandiol, 1,6-hexanediol, neopentyl glycol ), diethylene glycol, 3-methyl-1,5-pentanediol, polytetramethylene etherglycol (PTMG), and mixtures thereof It is preferably selected, but is not limited thereto.

The solvent uses a mixed solvent of water and acetone to prepare a water-dispersible polyurethane resin. The mixed solvent of water and acetone is dimethylformamide (DMF), which is used to prepare a conventional polyurethane resin. Unlike solvents regulated as carcinogens such as methyl ethyl ketone (MEK) and toluene, it is a non-toxic solvent, so the safety of workers manufacturing water-dispersed polyurethane resin can be guaranteed. In some cases, dimethylol propionic acid (DMPA) having a hydrophilic group may be added to increase the solubility of polyols and glycols.

In such a state in which the polyol, glycol, DMPA, and solvent are mixed, the temperature of the stirrer is increased to 70 to 80 ° C., and then stirred for 30 minutes so that they are uniformly mixed with each other.

The prepolymer forming step (S200) means a step of adding diisocyanate to a solvent to form a prepolymer having an isocyanate group (-NCO) molecular weight of 3.4 to 4.6%.

In the polyol dissolving step (S100), diisocyanate is continuously added to the solvent in a state where the polyol is dissolved in the solvent to form a prepolymer having an isocyanate group (-NCO) at the end. Here, diisocyanate (OCN-R-NCO) means a composition containing two isocyanate groups at both ends.

In the case of the prepolymer having an isocyanate group (-NCO) at the terminal, the prepolymer is formed such that the isocyanate group accounts for 3.4 to 4.6% of the total molecular weight of the prepolymer. That is, in the prepolymer, the polyol excluding the isocyanate group and the diisocyanate react to form the prepolymer so that the molecular weight is 95.4 to 96.6%, and the remaining 3.4 to 4.6% is isocyanate group at the end of the prepolymer. It means that it remains.

If the molecular weight of the isocyanate group is less than 3.4%, silicone diol to be described below may not be sufficiently bound, and if the molecular weight of the isocyanate group exceeds 4.6%, it is not possible to obtain a high molecular weight water-dispersible polyurethane resin. Therefore, to ensure that the isocyanate group exists within this molecular weight range, FT-IR is used to continuously check to match the corresponding range.

Here, the diisocyanate is 1,4-cyclohexyl diisocyanate (CHDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane -4,4-diisocyanate (dicyclohexylmethane-4,4diisocyanate, H12MDI, hydrogenated MDI, HMDI), 1,3-bisisocyanatomethylcyclohexane (1,3-Bis(Isocyanatomethyl)Cyclohexane, H6XDI, hydrogenated XDI, HXDI) and mixtures thereof, among which isophorone diisocyanate is most preferred.

In this way, after adding diisocyanate to the solvent, the polyol and diisocyanate are reacted through stirring for 2 to 3 hours while maintaining the temperature of the stirrer at 70 to 80 ° C. as in the polyol dissolution step (S100) to form a prepolymer. do.

Next, a neutralizing agent is added to the prepolymer, and the neutralization reaction is performed for 30 minutes in a state where the temperature of the stirrer is lowered to 30 to 40° C. to obtain an ionized prepolymer. Here, as the neutralizer, triethanolamine (TEA) or diethanolamine (DEA) is preferably used, but is not limited thereto.

In the first chain extension step (S300), a polyurethane prepolymer in which an isocyanate group (-NCO) having a molecular weight of 0.4 to 1.6% is formed at the end by adding a chain extender to the prepolymer to extend the chain including polyol and diisocyanate. means the step of forming

A chain extender is intermittently added several times to a prepolymer containing polyol and diisocyanate, so that the polyol and isocyanate form a chain through the chain extender, and the chain is extended by adding the chain extender several times. A polyurethane prepolymer is prepared.

At this time, the intermittent addition of the chain extender is to make the molecular weight of the isocyanate group (-NCO) formed at the end of the polyurethane prepolymer to be 0.4 to 1.6%. If the molecular weight of the isocyanate group formed at the end of the polyurethane prepolymer is less than 0.4%, silicone diol cannot be bonded in a sufficient amount afterwards, resulting in poor scratch resistance of the final coating product, and the molecular weight of the isocyanate group is 1.6%. If it exceeds, there is a problem that the polyurethane prepolymer does not have sufficient chain extension and the content of silicon diol becomes excessive.

In this way, in the first chain extension step (S300), the reaction is carried out by stirring for 2 to 3 hours while maintaining the temperature of the stirrer at 30 ° C or less, and the chain extender is intermittently added during stirring. In the present invention, piperazine is most preferred as a chain extender, but is not limited thereto.

The silicone diol addition and secondary chain extension step (S400) means a step of obtaining a water-dispersed polyurethane resin containing silicone by adding silicone diol to the polyurethane prepolymer and extending the chain.

Through the first chain extension step (S300), silicon diol is added to the polyurethane prepolymer having an isocyanate group (-NCO) having a molecular weight of 0.4 to 1.6% at the end, and the reaction between the silicon diol and isocyanate causes chain is extended to form a water-dispersed polyurethane resin containing silicone at the end. When silicone is included in the water-dispersed polyurethane resin, frictional resistance of the surface can be reduced and flexibility can be imparted to the surface, so scratch resistance can be improved when it is prepared as a coating agent. Specifically, by including silicon diol, the surface tension of the coating agent is adjusted to increase wettability with the BOPP film during coating, and the surface energy of the coated surface is adjusted to provide appropriate slip and scratch resistance.

Here, silicon diol has a structure that includes a plurality of silicon and has two hydroxyl groups (-OH) at the ends, and silicon diol of Formula 1 or Formula 2 below is added. In the case of Chemical Formula 1, a structure in which polysiloxane is grafted between diol structures, and in the case of Chemical Formula 2, a structure in which a hydroxyl group exists at each end of a polysilicon structure corresponds to a structure.

<Formula 1>

<Formula 2>

As in the polyol dissolution step (S100), the silicone diol is added after the temperature of the stirrer is increased to 70 to 80 ° C, and the polyurethane prepolymer is maintained at 70 to 80 ° C. Then, the silicone diol is added. After lowering the temperature of the stirrer to 30 ° C. or less, a chain extender is intermittently added to prepare a polyurethane coating agent containing silicone. Here, the chain extender is most preferably piperazine as in the first chain extension step (S300), but is not limited thereto.

As such, the polyurethane particles of the polyurethane coating agent containing silicone have a particle size of 1,000 to 3,000 nm, which is larger than that of polyurethane generally sold, as shown in FIG. 2, through which a separate matting agent It is possible to show matte without adding. If the particle size of polyurethane is less than 1,000 nm, the matte effect cannot be properly displayed, and if it exceeds 3,000 nm, the particle size is too large, making it difficult to coat with a uniform surface.

The additive adding step (S500) means a step of forming a water-dispersed polyurethane coating agent by adding additives such as a curing agent, a thickener, a dispersing agent, a leveling agent, and an antifoaming agent to a water-dispersed polyurethane resin containing silicone.

The hardener is a component added to not only harden the coating agent after coating it on the BOPP film but also to increase scratch resistance. In the present invention, HDI-trimer (aliphatic hexamethylene-1,6-diisocyanater) is used as the hardener. . It is preferable to add 3 to 5 parts by weight of the curing agent. If the curing agent is added in an amount less than 3 parts by weight, the desired level of scratch resistance and abrasion resistance cannot be obtained. There is a disadvantage in that it hardens within a short time during coating, and thus uniform coating may not be achieved.

A thickener is added to increase the viscosity of the polyurethane coating. In the present invention, a thickener containing a urea derivative is used to increase the viscosity of the coating and to prevent the polyurethane particles in the coating from sinking. Anti-settling is also possibly added. It is preferable to add 0.1 to 1 part by weight of the thickener. If the thickener is less than 0.1 part by weight, the viscosity of the polyurethane coating agent is low, and the coating may not be smoothly performed. will harm

A dispersing agent is a component included to prevent aggregation of polyurethane through steric stabilization and uniformly disperse polyurethane, and corresponds to a mixture containing titanium dioxide. It is preferable to add 1 to 2 parts by weight of the dispersant. When the dispersant is less than 1 part by weight, aggregation of polyurethane particles cannot be prevented, and when 2 parts by weight is added, wear resistance is deteriorated.

A leveling agent is a component added to reduce surface tension and increase wetting and leveling, and corresponds to a polyether-modified siloxane solution. It is preferable to add 0.2 to 0.5 parts by weight of such a leveling agent. When added in less than 0.2 parts by weight, the leveling effect cannot be properly observed, and when 0.5 parts by weight is added, wear resistance is adversely affected.

An antifoaming agent is added to destroy bubbles generated during the manufacture and use of a polyurethane coating agent, and corresponds to a hydrophobic component based on polysiloxane and polyglycol. Compatibility with additives is important because these antifoaming agents must remove all bubbles generated after the addition of other additives, and it is preferable to add them last because all bubbles generated by high-speed stirring when mixing the coating agent must be removed. do. Here, it is preferable to add 1 to 5 parts by weight of the antifoamer. If it is less than 1 part by weight, it takes a lot of time to remove bubbles and bubbles cannot be completely removed, and if it exceeds 5 parts by weight, it may cause denaturation of other additives. there is. Among them, the most preferred content of the antifoaming agent corresponds to 5 parts by weight.

Hereinafter, the method for preparing a scratch-resistant coating agent for a biaxially stretched polypropylene film of the present invention will be described in more detail.

<Example 1>

After adding polyol, polytetramethylene etherglycol (PTMG), dimethylol propionic acid (DMPA), and a catalyst to a 1,000ml reactor, the reaction was performed at 80°C for 30 minutes, and isophorone diisocyanate (isophoron diisocyanate, IPDI) was additionally added to carry out polymerization for about 2 hours. At this time, through FT-IR analysis, it is confirmed whether the residual isocyanate group has reached the target value of 3.4 to 4.6% to form a prepolymer, and then the temperature of the reactor is lowered to 30 ° C or less.

Then, triethanolamine (TEA), a neutralizing agent, is added to neutralize the mixture for 30 minutes to obtain an ionized prepolymer. After lowering the reaction temperature to 25° C., deionized distilled water was dispersed at a constant rate while rapidly stirring, and then a chain extender, piperazine, was added for 2 hours to form a polyurethane prepolymer. Then, after raising the temperature of the reactor to 80℃ again, silicone diol is added to mix with the polyurethane prepolymer. Polyurethane resin containing was synthesized.

Table 1 below shows a synthesis formulation table in which polyurethane resins were synthesized by preparing different types of polyols, and components except for polyols were identically formulated.

M.w. Example 1-1
(parts by weight) Example 1-2
(parts by weight) Example 1-3
(parts by weight) Example 1-4
(parts by weight) polyether polyol 2,000 60 - - - polyester polyol 2,000 - 60 - - polycarbonate polyol 2,000 - - 60 - polyacrylic polyol 2,000 - - - 60 silicon diol 1,000 0.8 0.8 0.8 0.8 1,4-butanediol 90.12 6 6 6 6 DMPA 134.13 2.6 2.6 2.6 2.6 IPDI 222.28 33 33 33 33 TEA 101.19 2 2 2 2 piperazine 60.1 5 5 5 5 solvent, catalyst Acetone, distilled water, DBTDL

The results of analyzing the water-dispersed polyurethane resins of synthesized Examples 1-1 to 1-4 using FT-IR can be confirmed through FIG. 3 . In the FT-IR spectra of the water-dispersed polyurethane resin, the -OH characteristic peak around 3400 cm ^-1 caused by polyol disappeared, while the -NH- characteristic peak of urethane was observed around 3300 cm ^-1 , and 1728 cm ^-1 A characteristic peak due to the carbonyl group of urethane was observed in the vicinity, and a -NH- bending peak was observed around 1640 cm ^-1 . In the end, when looking at the water-dispersed polyurethane resin in which the reaction is completed by chain extension in the FT-IR spectra, -NH- characteristic peaks around 3300 cm ^-1 and peaks due to carbonyl groups around 1728 cm ^-1 are grown, and 2270 cm ^-1 It is analyzed that the characteristic peak attributable to nearby isocyanates has almost disappeared. In addition, as a result of FT-IR analysis of Examples 1-2 and 1-3 using a carbonate-based polyol, an absorption peak in the fingerprint region showing characteristics inherent in a carbonate (-O-COO-C) group near 1250 cm ^-1 appears can confirm that

Next, in order to analyze the physical properties of the synthesized water-dispersed polyurethane, it was left at room temperature for 5 days by a casting method and dried at 50 ° C. for 5 hours to prepare a film. Mechanical properties of the prepared film can be confirmed through FIG. 4 and Table 2. 5 is a differential scanning calorimetry (DSC) measurement graph, FIG. 6 is a thermogravimetric analysis (TGA) graph, and FIG. 7 is a densitometric (DMA) graph.

tensile strength
(kgf/cm²) Elongation (%) 100% modulus
(kgf/cm²) Example 1-1 289.6 611.2 63.69 Example 1-2 222.6 478.2 119.9 Examples 1-3 353.4 282.2 181.2 Example 1-4 303.9 293.1 204.5

<Example 2>

Table 3 shows the results of confirming the surface slipperiness, adhesion, hardness and abrasion resistance of the water-dispersed polyurethane resin in the state where the content of the silicone diol of Formula 1 and the silicone diol of Formula 2 were respectively adjusted. In the case of other compositions except for the type and content of silicon diol, 60 parts by weight of polyol, 6 parts by weight of 1,4-butanediol, 2.6 parts by weight of DMPA, 33 parts by weight of IPDI, 2 parts by weight of TEA, and 5 parts by weight of piperazine were uniformly mixed. did Among the results, it can be confirmed that the polyurethane coating agent containing 0.8 parts by weight of Chemical Formula 1 has the most suitable surface slip properties, adhesion, hardness and abrasion resistance.

M.w. content
(parts by weight) surface slipperiness adhesiveness Hardness wear resistance

Formula 1

1,000 0.4 3 ○ × 30 0.8 4 ○ ○ 60 1.6 5 △ △ 80 Formula 2

1,000 0.4 2 ○ × 30 0.8 2.5 ○ ○ 40 1.6 4 ○ △ 60

○: Good, △: Normal, ×: Bad

8 shows the light transmittance after coating Example 2-1 in which 0.8 parts by weight of Chemical Formula 1, Comparative Example not containing silicon diol, and Example 2-2 in which 0.8 parts by weight of Chemical Formula 2 were added were coated on a BOPP film, respectively. This is a comparison picture. All test specimens were tested by fixing them with gloss 14GU after drying. In the case of the comparative example, the effect of reducing surface gloss was obvious, but it was confirmed that the surface haze was large and the coating surface was relatively uneven compared to the coating agent containing silicon diol. can In contrast, in the case of Example 2-1 and Example 2-2, it can be confirmed that the light transmittance was excellent and the haze of the surface was also small.

<Example 3>

Polyol 60 parts by weight, silicon diol 0.8 parts by weight, 1,4-butanediol 6 parts by weight, DMPA 2.6 parts by weight, IPDI 33 parts by weight, TEA 2 parts by weight, piperazine 5 parts by weight. HDI-trimer (aliphatic hexamethylene-1,6-diisocyanate) was added as a curing agent to confirm the abrasion resistance of the coating agent according to the amount added. The abrasion resistance test conditions were evaluated for abrasion resistance according to the number of revolutions at a weight of 500 g, and in the case of pencil hardness, the hardness was confirmed at H ~ 2H.

As shown in Table 4, as a result of coating the BOPP film with 0 to 5 parts by weight of the curing agent and then rotating it 50 times at 50 rpm using a weight of 500 g, it can be confirmed that the abrasion resistance becomes excellent when the curing agent is 3 parts by weight or more. It was found that the coating agent added in 5 parts by weight had the best wear resistance.

0 parts by weight 1 part by weight 3 parts by weight 5 parts by weight

In addition, Figure 9 is a photograph of the pencil hardness evaluation of the water-dispersed polyurethane coating agent to which 5 parts by weight of the curing agent was added, and it was confirmed that excellent scratch resistance appeared in 1H and 2H.

<Example 4>

Polyol 60 parts by weight, silicon diol 0.8 parts by weight, 1,4-butanediol 6 parts by weight, DMPA 2.6 parts by weight, IPDI 33 parts by weight, TEA 2 parts by weight, piperazine 5 parts by weight. A thickener was added to confirm the abrasion resistance of the coating agent according to the amount added.

As shown in Table 5, as a result of coating the BOPP film with 0.5 to 3 parts by weight of the thickener and then rotating it 50 times at 50 rpm using a weight of 500 g, the best wear resistance was confirmed when 0.5 part by weight of the thickener was added. there was.

0.5 parts by weight 1 part by weight 3 parts by weight

<Example 5>

Polyol 60 parts by weight, silicon diol 0.8 parts by weight, 1,4-butanediol 6 parts by weight, DMPA 2.6 parts by weight, IPDI 33 parts by weight, TEA 2 parts by weight, piperazine 5 parts by weight. A dispersant was added to confirm the abrasion resistance of the coating agent according to the amount added.

As shown in Table 6, as a result of coating the BOPP film with 1 to 5 parts by weight of the dispersant and then rotating it 50 times at 50 rpm using a weight of 500 g, the best wear resistance was obtained when 1 to 2 parts by weight of the dispersant was added. It was confirmed, and at 3 parts by weight or more, the wear resistance was lower than that of 1 to 2 parts by weight, but it was confirmed that the wear resistance was relatively excellent compared to other coating agents.

1 part by weight 2 parts by weight 3 parts by weight 5 parts by weight

As described above, when a water-dispersible polyurethane coating agent containing silicone is prepared using the method for manufacturing a scratch-resistant coating agent for a biaxially stretched polypropylene film according to the present invention and then coated on a BOPP film, wear resistance and scratch resistance are obtained by silicone In addition to this increase, matte coating can be achieved without applying a separate matting agent due to polyurethane particles having a larger size than before.

The present invention is not limited to the above embodiments, and the scope of application is diverse, and various modifications and implementations are possible without departing from the gist of the present invention claimed in the claims.

S100: polyol dissolution step
S200: prepolymer formation step
S300: 1st chain extension step
S400: Silicon diol addition and secondary chain extension step
S500: additive addition step

Claims (3)

A polyol dissolution step of dissolving the polyol and glycol in the solvent by stirring after putting the polyol, glycol, and solvent into a reactor;
a prepolymer formation step of forming a prepolymer having an isocyanate group (-NCO) molecular weight of 3.4 to 4.6% by adding diisocyanate to the solvent in which the polyol and the glycol are dissolved;
Primary chain extension to form a polyurethane prepolymer having an isocyanate group (-NCO) having a molecular weight of 0.4 to 1.6% at the end by adding a chain extender to the prepolymer to extend the chain including the polyol and the diisocyanate step;
Adding silicone diol to the polyurethane prepolymer and extending the chain to obtain a water-dispersed polyurethane resin containing silicone diol and a secondary chain extension step; and
Biaxially stretched polypropylene film comprising a; additive addition step of forming a water-dispersed polyurethane coating agent by adding additives such as a curing agent, a thickener, a dispersing agent, a leveling agent, and an antifoaming agent to the water-dispersible polyurethane resin containing silicone. A method for producing a scratch-resistant coating agent for use. According to claim 1,
The silicone diol is a scratch-resistant coating agent manufacturing method for a biaxially stretched polypropylene film, characterized in that any one of the following formula (1) or formula (2).
<Formula 1>

<Formula 2>

According to claim 1,
3 to 5 parts by weight of the curing agent, 0.1 to 1 part by weight of the thickener, 1 to 2 parts by weight of the dispersing agent, 0.2 to 0.5 parts by weight of the leveling agent, and 1 to 5 parts by weight of the antifoaming agent. A method for producing a scratch-resistant coating agent for a biaxially stretched polypropylene film.

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