Primer composition

Abstract

The present invention relates to a primer composition that can be applied to a decorative sheet.

Description

Primer composition

[0001] The present invention relates to a primer composition applicable to deco sheets.

[0002]

[0003] Gravure printing has been primarily used as a printing method applied to deco sheets, and various technologies for manufacturing deco sheets using this method have been proposed. For example, Korean Patent Publication No. 2021-0077834 discloses an interior film and a method for manufacturing the same, comprising: an adhesive layer comprising an acrylic copolymer, water, a tackifier, and an additive; a substrate layer comprising a heat stabilizer and a PVC resin; and a printing layer comprising a solvent having a boiling point of 120°C or lower.

[0004] While gravure printing enables high-speed mass production, it has several drawbacks: significant costs and time are incurred for producing copper plates for design changes; there are limitations in realizing high-resolution images or selecting various images; time and costs are incurred due to process changes; and there is a high risk of safety accidents. To address these issues, methods using digital printing are being attempted.

[0005] According to the digital printing method, the deco sheet can be manufactured by heat laminating a transparent polyvinyl chloride (PVC) layer onto a UV ink printing layer. Since the UV ink printing layer has poor adhesion to the transparent PVC layer, the durability of the finished product is typically ensured by using a primer or adhesive to provide interlayer adhesion. However, conventional primer compositions have insufficient interlayer adhesion, which causes the deco sheet to lift, and conventional adhesive compositions have problems such as blocking after drying.

[0006] Accordingly, there is a need to develop a primer composition that provides sufficient adhesion between the UV ink printing layer and the transparent PVC layer, does not cause blocking phenomena so that semi-finished products can be stored easily, and has high weather resistance.

[0007]

[0008] The present invention provides a primer composition that provides sufficient adhesion between a UV ink printing layer and a transparent polyvinyl chloride (PVC) layer, prevents blocking, and has high weather resistance.

[0009]

[0010] The present invention provides a primer composition comprising a vinyl chloride-vinyl acetate copolymer resin and a polyester-modified urethane resin, wherein the primer composition comprises 13 to 22 weight% of the vinyl chloride-vinyl acetate copolymer resin and 1 to 12 weight% of the polyester-modified urethane resin based on the total weight of the primer composition, and wherein the copolymerization ratio of vinyl chloride to vinyl acetate of the vinyl chloride-vinyl acetate copolymer resin is 1.5 to 9:1 by weight.

[0011]

[0012] The present invention provides a primer composition that imparts sufficient adhesion between a UV ink printing layer and a transparent PVC layer, does not cause blocking phenomena, and has high weather resistance. The primer composition according to the present invention can be applied to a deco sheet comprising a printing layer formed by digital inkjet, in which case thermal lamination (heat sealing) of the UV ink layer and the PVC layer is possible. A deco sheet to which the primer composition of the present invention is applied has excellent resolution, peel strength, and weather resistance, and is easy to store as a semi-finished product in roll form.

[0013]

[0014] The present invention will be described in detail below. However, it is not limited to the following description, and each component may be modified in various ways or selectively combined as needed. Accordingly, it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0015] As used herein, the “glass transition temperature” is measured by conventional methods known in the art, for example, by thermomechanical analysis (TMA) or differential scanning calorimetry (DSC). The “weight-average molecular weight” is measured by conventional methods known in the art, for example, by gel permeation chromatography (GPC).

[0016]

[0017] Primer Composition

[0018] The primer composition of the present invention comprises a vinyl chloride-vinyl acetate copolymer resin and a polyester-modified urethane resin.

[0019]

[0020] Vinyl chloride-vinyl acetate copolymer resin

[0021] The primer composition of the present invention comprises a vinyl chloride-vinyl acetate copolymer resin. The vinyl chloride-vinyl acetate copolymer resin serves as the main resin, providing excellent adhesion between the UV ink printing layer and the transparent PVC layer, preventing blocking phenomena, and enabling thermal lamination between the printing layer and the transparent PVC layer.

[0022] The copolymerization ratio of vinyl chloride to vinyl acetate in the above vinyl chloride-vinyl acetate copolymer resin may be a weight ratio of 1.5 to 9:1, for example, 2 to 6:1. If the copolymerization ratio of vinyl chloride to vinyl acetate is less than the aforementioned range, blocking may occur or adhesion may be reduced, and if it exceeds the aforementioned range, adhesion may be reduced.

[0023] The glass transition temperature of the above vinyl chloride-vinyl acetate copolymer resin may be 55°C or higher, for example, 55 to 75°C. If the glass transition temperature is below the aforementioned range, blocking may occur, and if it exceeds the aforementioned range, adhesion may be reduced.

[0024] The weight-average molecular weight of the vinyl chloride-vinyl acetate copolymer resin may be 50,000 to 95,000 g / mol, for example, 60,000 to 85,000 g / mol. If the weight-average molecular weight is below the aforementioned range, blocking may occur and adhesion may be reduced, and if it exceeds the aforementioned range, coating failure may occur due to excessive viscosity.

[0025] The primer composition of the present invention may comprise 13 to 22 weight percent, for example 15 to 19 weight percent, of the vinyl chloride-vinyl acetate copolymer resin based on the total weight of the primer composition. If the content of the vinyl chloride-vinyl acetate copolymer resin is less than the aforementioned range, the adhesion may be reduced and the viscosity of the coating solution may be lowered, making it difficult to form a film thickness; if it exceeds the aforementioned range, the viscosity of the coating solution may be higher, reducing the coating performance and making it difficult to apply uniformly.

[0026]

[0027] Polyester-modified urethane resin

[0028] The primer composition of the present invention comprises a polyester-modified urethane resin. The polyester-modified urethane resin serves as an auxiliary resin and plays a role in further improving adhesion.

[0029] The glass transition temperature of the above polyester-modified urethane resin may be 10 to 25°C, for example, 10 to 15°C. If the glass transition temperature is below the aforementioned range, blocking may occur, and if it exceeds the aforementioned range, adhesion may be reduced.

[0030] The weight-average molecular weight of the above polyester-modified urethane resin may be 55,000 to 95,000 g / mol, for example, 65,000 to 85,000 g / mol. If the weight-average molecular weight is below the aforementioned range, blocking may occur and adhesion may be reduced, and if it exceeds the aforementioned range, coating failure may occur due to excessive viscosity.

[0031] The primer composition of the present invention may comprise 1 to 12 weight percent, for example, 1 to 5 weight percent, of the polyester-modified urethane resin based on the total weight of the primer composition. If the content of the polyester-modified urethane resin is less than the aforementioned range, the adhesion may be reduced and the viscosity of the coating solution may be lowered, making it difficult to form a film thickness; if it exceeds the aforementioned range, the viscosity of the coating solution may be higher, reducing the coating performance and making it difficult to apply uniformly.

[0032]

[0033] menstruum

[0034] The primer composition of the present invention may include a solvent. The solvent serves to penetrate the resin into the UV ink layer.

[0035] As the above solvent, a fast-drying solvent may be used, in which case rapid drying properties can be imparted. As the above solvent, propylene glycol methyl ether acetate (PMA), ethylene glycol n-butyl ether acetate (BGAc), ethylene glycol monobutyl ether (BGA), gamma butyrolactone (G-BL), diethylene glycol diethyl ether (DEDG), diethylene glycol methyl ethyl ether (MEDG), ethyl acetate (EA), butyl acetate (BA), acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, alcohols (e.g., isopropyl alcohol (IPA)), etc. may be used. The above solvent may be used alone or in a mixture of two or more types.

[0036] The primer composition of the present invention may include the solvent in an amount satisfying 100% by weight of the total weight of the primer composition.

[0037]

[0038] additives

[0039] The primer composition of the present invention may further include additives commonly used in the relevant art. Non-limiting examples of said additives include UV absorbers, plasticizers, etc.

[0040] UV absorbers further improve the weather resistance of the primer composition and the product to which the composition is applied (e.g., deco sheet), and in particular, serve to prevent discoloration of the UV ink layer. Tinuvin 400 (BASF), Tinuvin 328 (BASF), Tinuvin 928 (BASF), Tinuvin 1130 (BASF), Tinuvin 384 (BASF), etc., may be used as UV absorbers. These may be used alone or in a mixture of two or more types.

[0041] The plasticizer further enhances the flexibility of the primer composition and the product to which the composition is applied (e.g., deco sheet), thereby facilitating product processability. Environmentally friendly plasticizers may be used as the plasticizer. Examples of environmentally friendly plasticizers include DOTP, ECO-DEHCH (Hanwha Solution Chemical), Hexamoll DINCH, W-230-H (DIC), W-1430-EL (DIC), etc. These may be used individually or in a mixture of two or more types.

[0042] Each additive may be used in an amount typically used in the relevant technical field. For example, the primer composition of the present invention may contain 0.2 to 5 weight%, for example 0.3 to 0.7 weight% of each additive, based on the total weight of the primer composition.

[0043]

[0044] Deco Sheet

[0045] The present invention provides a deco sheet in which a substrate, a UV ink layer, a primer layer, and a transparent layer are sequentially laminated. The deco sheet can be applied to interior films, flooring materials, etc.

[0046] The above material may be formed from polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), vinyl chloride, copolymers thereof, etc. These may be used alone or in a mixture of two or more types. For example, the above material may be formed from colored PVC.

[0047] The above UV ink layer can be formed using an inkjet method, for example, a single-pass high-speed inkjet method. A single-pass high-speed inkjet method is a system in which the head of a digital printer is fixed and ink is jetted as the material to be printed passes through.

[0048] The above UV ink layer is formed from a UV ink composition. The above UV ink composition may be any that is used in the relevant technical field without special limitations, and for example, a UV ink composition comprising a pigment, a urethane (meth)acrylate oligomer, a (meth)acrylate monomer, a caprolactam-based compound, and a UV initiator may be used.

[0049] The above primer layer can be formed with the primer composition according to the present invention described above.

[0050] The above transparent layer may be formed from polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), vinyl chloride, copolymers thereof, etc. These may be used alone or in a mixture of two or more types. For example, the above transparent layer may be formed from transparent PVC.

[0051]

[0052] The present invention will be explained in more detail through the following examples. However, the following examples are intended only to aid in understanding the present invention, and the scope of the present invention is not limited to these examples in any way.

[0053]

[0054] [Preparation Example 1-6: Preparation of Vinyl Chloride-Vinyl Acetate Copolymer Resin]

[0055] Vinyl chloride monomer and vinyl acetate monomer were polymerized in suspension to produce vinyl chloride-vinyl acetate copolymer resins of each preparation example having the composition and physical properties listed in Table 1 below.

[0056]

[0057]

[0058]

[0059] [Examples 1-7: Preparation of Primer Composition]

[0060] Primer compositions for each example were prepared according to the composition of Table 2 below.

[0061]

[0062]

[0063]

[0064] [Comparative Examples 1-5: Preparation of Primer Compositions]

[0065] Primer compositions for each comparative example were prepared according to the compositions in Table 3 below.

[0066]

[0067]

[0068] Preparation Example 1: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 10 : 0, Mw 69,305 g / mol, Tg 82 ℃)

[0069] Preparation Example 2: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 5.25 : 1, Mw 75,612 g / mol, Tg 72 ℃)

[0070] Preparation Example 3: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 2.03 : 1, Mw 79,603 g / mol, Tg 64 ℃)

[0071] Preparation Example 4: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 2.03 : 1, Mw 62,980 g / mol, Tg 50 ℃)

[0072] Preparation Example 5: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 1:1, Mw 85,118 g / mol, Tg 55 ℃)

[0073] Preparation Example 6: Vinyl chloride-vinyl acetate copolymer resin (copolymerization ratio (weight ratio) of vinyl chloride and vinyl acetate 0.66 : 1, Mw 33,000 g / mol, Tg 50 ℃)

[0074] Resin 2: Polyester-modified urethane resin (Mw 75,000 g / mol, Tg 10 ℃)

[0075] MEK: Methyl ethyl ketone

[0076] IPA: Isopropyl alcohol

[0077] Additives: UV absorber (Tinuvin 400 (BASF), diluted 85% with 1-methoxy-2-propanol)

[0078]

[0079] [Physical Property Evaluation]

[0080] After measuring the physical properties using the primer compositions of each example and comparative example according to the following method, the results are shown in Tables 4 and 5 below.

[0081]

[0082] viscosity

[0083] The viscosity of each primer composition was measured at 50 rpm using a #2 spindle and a DV-1 viscometer.

[0084]

[0085] Sample preparation

[0086] Each primer composition was coated onto DP UV printed paper (DM) using a bar coater, and a specimen (dry film thickness: 2-3 μm) was prepared by drying in a 45°C dry oven for 2 minutes.

[0087]

[0088] Coating properties

[0089] For each specimen, coating uniformity was checked using a thickness gauge, and uncoated areas were judged visually. It was judged as OK if the thickness of the dry film over the entire area was uniform at 2-3 μm using a thickness gauge and there were no uncoated areas upon visual inspection, and as NG if it did not meet the above criteria.

[0090]

[0091] Peel strength

[0092] A transparent PVC sheet was placed on each specimen and fixed to a steel plate. A steel plate heated to 270°C was placed together with the specimen in a 100°C laminating machine to perform heat lamination. The specimens were cut to a width of 1 inch, and a tensile strength test was conducted by fixing the transparent sheet and the printed paper to a Universal Testing Machine (UTM, ST-1003) to measure the peel strength (kgf / inch).

[0093]

[0094] blocking

[0095] Each specimen was cut to a size of 10 x 10 (cm), stacked in 7 layers, and a 20 kg load was applied over them. The specimens were then placed in a 50 ℃ dry oven for 7 days, and the printed paper was peeled off daily to check for the transfer of ink and primer to the opposite specimen, and evaluated according to the following criteria.

[0096] [metewand]

[0097] ○: No metastasis, β: Partial metastasis, X: Metastasis over the entire area

[0098]

[0099] Weather resistance

[0100] A transparent PVC sheet was placed over each specimen, fixed to a steel plate, and heat-laminated in a 150°C laminating machine. The specimens were cut into 7 x 5 cm pieces, exposed to a Weather Ometer (WOM) for 300 hours, and then the ΔE value was checked by measuring the color with a colorimeter.

[0101]

[0102]

[0103]

[0104]

[0105] As shown in Tables 4 and 5 above, the primer compositions of Examples 1-7 according to the present invention exhibited excellent physical properties across all measured items. On the other hand, the primer compositions of Comparative Examples 1, 3, and 4, which used a vinyl chloride-vinyl acetate copolymer resin (Preparation Examples 1, 5, and 6) in which the copolymerization ratio of vinyl chloride and vinyl acetate was outside the scope of the present invention, and Comparative Examples 2 and 5, which used a vinyl chloride-vinyl acetate copolymer resin in an amount outside the scope of the present invention, exhibited inferior physical properties across all measured items compared to Examples 1-7.

[0106]

[0107] The present invention provides a primer composition that provides sufficient adhesion between a UV ink printing layer and a transparent polyvinyl chloride (PVC) layer, prevents blocking, and has high weather resistance.

Claims

1. A primer composition comprising a vinyl chloride-vinyl acetate copolymer resin and a polyester-modified urethane resin, wherein Based on the total weight of the primer composition, it comprises 13 to 22 weight% of the vinyl chloride-vinyl acetate copolymer resin and 1 to 12 weight% of the polyester-modified urethane resin, and A primer composition in which the copolymerization ratio of vinyl chloride to vinyl acetate of the above-mentioned vinyl chloride-vinyl acetate copolymer resin is 1.5 to 9:1 by weight.

2. A primer composition according to claim 1, wherein the glass transition temperature of the vinyl chloride-vinyl acetate copolymer resin is 55 ℃ or higher and the weight-average molecular weight is 50,000 to 95,000 g / mol.

3. A primer composition according to claim 1, wherein the polyester-modified urethane resin has a glass transition temperature of 10 to 25 ℃ and a weight-average molecular weight of 55,000 to 95,000 g / mol.

4. A primer composition according to claim 1, further comprising 0.2 to 5 weight percent of a UV absorber based on the total weight of the primer composition.

5. A deco sheet in which a substrate, a UV ink layer, a primer layer, and a transparent layer are sequentially laminated, A deco sheet in which the primer layer is formed from a primer composition of any one of claims 1 to 4.

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