Paper product coating and white cardboard

Abstract

The present application relates to the field of papermaking technology, and specifically discloses a paper product coating and white cardboard. The paper product coating provided in the present application comprises the following components in parts by weight: 30‑50 parts of silicone-modified acrylic resin, 10‑20 parts of ECOAT waterborne polyurethane-modified alkyd resin, 3‑10 parts of silica, 1 part of defoamer, 1‑2 parts of leveling agent and 150‑170 parts of water; further, the silica is a mixture of 1‑5 μm silica, 100‑200 nm silica and 30‑50 nm silica; the present application also provides a white cardboard, comprising a base paper layer and a coating formed on the surface of the base paper layer by the above-mentioned paper product coating. The water absorption of the white cardboard provided in the present application is 35‑45 g / m 2 The packaging material is prepared by printing and glazing the above-mentioned white card paper, and the obtained packaging material is not easy to stick together in a high temperature and high humidity environment.

Description

Technical Field

[0001] The present application relates to the technical field of papermaking, and in particular to a paper product coating and white cardboard. Background Art

[0002] As a paper with excellent comprehensive performance, white cardboard is widely used in the packaging of high-end products, such as medicines, cosmetics, electronic products and other fields. As a packaging material, it not only needs to have good physical properties, such as pressure resistance and moisture resistance, but also needs to have a high aesthetics to attract consumers. Lamination and glazing are two commonly used ways to improve the performance of packaging materials. Lamination is to cover the surface of the printed product with a thin plastic film to enhance its waterproof, anti-fouling and wear resistance, while glazing is to apply a layer of transparent varnish on the surface of the printed product to beautify the appearance while improving its moisture resistance.

[0003] However, the above method still has some defects during use. For example, although laminating on the existing white cardboard can effectively prevent water penetration and avoid the problem of adhesion between packaged items, the above method is not environmentally friendly and is contrary to the current green environmental protection trend. The glazing process mostly uses water-based varnish of polyacrylic acid system. Although this varnish can improve the water resistance and wear resistance of white cardboard, due to the certain water absorption of acrylic acid system coating, it is easy to cause the packaged items to stick in a high humidity environment, which seriously affects the safety and appearance quality of the packaged items.

[0004] Therefore, developing a paper product coating is of great significance for improving the performance of white cardboard. Summary of the invention

[0005] In order to overcome the problem that the existing white cardboard is prone to sticking in a high temperature and high humidity environment after being glazed, the present application provides a paper product coating and white cardboard.

[0006] In the first aspect, the present application provides a paper product coating, which adopts the following technical solution: A paper product coating comprises the following components in parts by weight: 30-50 parts of organosilicon-modified acrylic resin, 10-20 parts of ECOAT waterborne polyurethane-modified alkyd resin, 3-10 parts of silicon dioxide, 1 part of defoamer, 1-2 parts of leveling agent and 150-170 parts of water.

[0007] The present invention adopts silicone modified acrylic resin, ECOAT waterborne polyurethane modified alkyd resin and silicon dioxide to prepare a paper product coating. The water absorption of the obtained white cardboard after the above paper product coating is applied to the white cardboard base paper is 35-45g / m 2The packaging prepared by printing and glazing the above-mentioned white cardboard is not easy to stick in a high temperature and high humidity environment. The specific reason is that the traditional printing varnish is easy to absorb moisture in a high temperature and high humidity environment. When the water absorption of the white cardboard is too low or too high, the moisture stays in the varnish layer, which makes the packaging easy to stick. After the paper product coating provided by the present application is coated on the white cardboard, the water absorption of the white cardboard can be maintained at 35-45g / m 2 The inventor of the present application has found that by using white cardboard with a water absorption within the above range to print varnished packaging materials, the white cardboard can absorb the water vapor in the varnish into the paper in time, reduce the moisture content in the varnish, and thus reduce the probability of adhesion of the packaging material.

[0008] In the present application, the combination of silicone-modified acrylic resin and ECOAT waterborne polyurethane-modified alkyd resin can not only enhance the adhesion and mechanical strength of the coating, but also adjust the permeability of water vapor, thereby adjusting the water absorption of white cardboard; silicon dioxide can adjust the rheology, stability and porosity of the coating, and can retain a certain air permeability while adjusting the water absorption of white cardboard, so as to avoid moisture accumulation inside the white cardboard. The addition of defoamer helps to eliminate bubbles and particle agglomeration in the coating, ensure uniform distribution of the coating, and improve the surface flatness and glossiness of the coating. Leveling agent can promote the rapid flow and flatness of the coating during application, reduce brush marks and orange peel effect, and make the final coating smoother and more delicate. In summary, the paper product coating provided in the present application can keep the water absorption of white cardboard within a specific range, and has a certain air permeability, and the packaging material prepared by it is not easy to stick, which effectively solves the adhesion problem of traditional white cardboard after glazing.

[0009] Optionally, the paper product coating comprises the following components in parts by weight: 35-45 parts of organosilicon-modified acrylic resin, 13-18 parts of ECOAT waterborne polyurethane-modified alkyd resin, 5-8 parts of silicon dioxide, 1 part of defoamer, 1-2 parts of leveling agent and 150-170 parts of water.

[0010] In this application, the addition amount of silicone-modified acrylic resin, ECOAT waterborne polyurethane-modified alkyd resin and silica will affect the water absorption and air permeability of paper product coatings. When the addition amount of silicone-modified acrylic resin, ECOAT waterborne polyurethane-modified alkyd resin or silica is too little, the water absorption of white cardboard is too high, the paper is easily deformed when damp and is not easy to print and polish; when the addition amount of silicone-modified acrylic resin or ECOAT waterborne polyurethane-modified alkyd resin is too high, the water absorption of the coating is poor, and under high temperature and high humidity environment, the water vapor in the environment cannot penetrate the varnish layer into the paper, causing water to slowly infiltrate the varnish layer in the varnish layer, causing the packaging to easily stick; when the addition amount of silica is too high, the coating is easy to powder after drying and curing. Therefore, this application found through experimental exploration that the weight of the three in the paper product coating is further controlled within the above range, the water absorption of the obtained white cardboard is suitable, and the white cardboard is not easy to stick even in a humid environment after printing and polishing.

[0011] In some embodiments, the weight parts of the organosilicon-modified acrylic resin may be 30-35 parts, 30-40 parts, 30-45 parts, 30-50 parts, 35-40 parts, 35-45 parts, 35-50 parts, 40-45 parts, 40-50 parts or 45-50 parts.

[0012] In a specific embodiment, the weight proportion of the organosilicon-modified acrylic resin may also be 30 parts, 35 parts, 40 parts, 45 parts or 50 parts.

[0013] In some embodiments, the weight parts of the ECOAT waterborne polyurethane modified alkyd resin can be 10-13 parts, 10-15 parts, 10-18 parts, 10-20 parts, 13-15 parts, 13-18 parts, 13-20 parts, 15-18 parts, 15-20 parts or 18-20 parts.

[0014] In a specific embodiment, the weight parts of the ECOAT waterborne polyurethane modified alkyd resin can also be 10 parts, 13 parts, 15 parts, 18 parts or 20 parts.

[0015] In some embodiments, the weight parts of the silicon dioxide may be 3-5 parts, 3-8 parts, 3-10 parts, 5-8 parts, 5-10 parts or 8-10 parts.

[0016] In a specific embodiment, the weight proportion of the silicon dioxide may also be 3 parts, 5 parts, 8 parts or 10 parts.

[0017] Optionally, the silicon dioxide is a mixture of 1-5 μm silicon dioxide, 100-200 nm silicon dioxide and 30-50 nm silicon dioxide.

[0018] Optionally, the weight ratio of the 1-5 μm silicon dioxide, the 100-200 nm silicon dioxide and the 30-50 nm silicon dioxide is 1:(1.5-2.5):(2-3).

[0019] The present invention adopts the above-mentioned silica particle size for compounding, and after the obtained paper product coating is coated on white cardboard, the water absorption of the white cardboard can be stabilized at 39-41g / m 2 range, and the transverse folding endurance is ≥85 times, which can meet the use requirements of packaging materials.

[0020] In some embodiments, the weight ratio of the 1-5 μm silica, 100-200 nm silica, and 30-50 nm silica can be 1:(1.5-1.8):2.5, 1:(1.5-2):2.5, 1:(1.5-2.3):2.5, 1:(1.5-2.5):2.5, 1:(1.8-2):2.5, 1:(1.8-2.3):2.5, 1:(1.8-2.5):2.5, 1: (2-2.3):2.5, 1:(2-2.5):2.5, 1:(2.2-2.5):2.5, 1:2:(2-2.2), 1:2:(2-2.5), 1:2:(2-2.8), 1:2:(2-3), 1:2:(2.2-2.5), 1:2:(2.2-2.8), 1:2:(2.2-3), 1:2:(2.5-2.8), 1:2:(2.5-3) or 1:2:(2.8-3).

[0021] In a specific embodiment, the weight ratio of the 1-5 μm silica, 100-200 nm silica and 30-50 nm silica can also be 1:1.5:2.5, 1:1.8:2.5, 1:2:2.5, 1:2.3:2.5, 1:2.5:2.5, 1:2:2, 1:2:2.2, 1:2:2.8 or 1:2:3.

[0022] Optionally, the weight ratio of the 1-5 μm silicon dioxide, the 100-200 nm silicon dioxide and the 30-50 nm silicon dioxide is 1:(1.8-2.3):(2.2-2.8).

[0023] In a second aspect, the present application provides a white cardboard, including a base paper layer and a coating formed on the surface of the base paper layer by a paper product coating.

[0024] Optionally, the water absorption of the white cardboard is 35-45g / m 2 .

[0025] Optionally, the coating has a weight of 8-12 g / m 2The basis weight of the base paper layer is 180-220g / m 2 .

[0026] In a specific embodiment, the coating has a basis weight of 10 g / m 2 The basis weight of the base paper layer is 200g / m 2 .

[0027] In summary, this application has the following beneficial effects: 1. This application uses silicone modified acrylic resin, ECOAT waterborne polyurethane modified alkyd resin and silicon dioxide to prepare a paper product coating, which is applied to the surface of white cardboard to form a coating on the surface of the white cardboard, so that the water absorption of the white cardboard is 35-45g / m 2 The above-mentioned white card paper is used for printing and glazing. The white card paper can absorb the water vapor in the printed varnish coating on the surface of the packaging product, reduce the moisture content in the varnish, and effectively prevent the packaging product from sticking in a humid environment.

[0028] 3. In the paper product coating provided in the present application, 1-5 μm silica, 100-200 nm silica and 30-50 nm silica are further compounded, and the weight ratio of the three is controlled within the range of 1: (1.5-2.5): (2-3), and the water absorption of the coated white cardboard is 39-41 g / m 2 The packaging material made of the above white cardboard has better anti-adhesion properties. DETAILED DESCRIPTION

[0029] The present application provides a paper product coating, comprising the following components in parts by weight: 30-50 parts of an organosilicon-modified acrylic resin, 10-20 parts of an ECOAT waterborne polyurethane-modified alkyd resin, 3-10 parts of silicon dioxide, 1 part of a defoamer, 1-2 parts of a leveling agent, and 150-170 parts of water; further, the paper product coating comprises the following components in parts by weight: 35-45 parts of an organosilicon-modified acrylic resin, 13-18 parts of an ECOAT waterborne polyurethane-modified alkyd resin, 5-8 parts of silicon dioxide, 1 part of a defoamer, 1-2 parts of a leveling agent, and 150-170 parts of water.

[0030] Wherein, the silicon dioxide is a mixture of 1-5 μm silicon dioxide, 100-200 nm silicon dioxide and 30-50 nm silicon dioxide; further, the weight ratio of the 1-5 μm silicon dioxide, 100-200 nm silicon dioxide and 30-50 nm silicon dioxide is 1: (1.5-2.5): (2-3); further, the weight ratio of the 1-5 μm silicon dioxide, 100-200 nm silicon dioxide and 30-50 nm silicon dioxide is 1: (1.8-2.3): (2.2-2.8).

[0031] The preparation method of the paper product coating is as follows: pouring each component into water in sequence, stirring evenly, and obtaining the paper product coating.

[0032] The present application provides a white cardboard, and the preparation method thereof is as follows: firstly, a white cardboard base paper is prepared, and then a paper product coating is applied to the upper and lower surfaces of the white cardboard base paper, and the coating amount is 8-12 g / m 2 , dry to obtain white card paper.

[0033] The white cardboard base paper provided in the present application can be prepared according to a method well known to those skilled in the art without any special limitation. The preparation method of the white cardboard base paper of the present application is as follows: the fiber raw material is crushed, refined, pulped, flowed, dehydrated, and dried to obtain a 200 g / m 2 The white cardboard base paper is as follows; the fiber raw materials include coniferous bleached chemical fiber, broadleaf bleached chemical fiber, coniferous bleached thermally ground mechanical fiber, and broadleaf bleached thermally ground mechanical fiber in a weight ratio of 1:8:2:4.

[0034] In the embodiments of the present application, the model of the silicone-modified acrylic resin is S-611, purchased from Wanjia Huixin; the model of the ECOAT waterborne polyurethane-modified alkyd resin is UR3304; the defoaming agent is a silicone-modified polysiloxane emulsion, model TEGO Foamex 30; the leveling agent is a polyether-modified siloxane polymer, model Lencolo 3157; the raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0035] The present application is further described in detail below in combination with preparation examples, embodiments, and performance testing experiments.

[0036] Preparation Example 1-12 Preparation Examples 1-12 each provide a paper product coating.

[0037] The difference between the above preparation examples is that the addition amount of each component in the paper product coating is shown in Table 1 below.

[0038] The preparation method of the paper product coating provided in Preparation Example 1-12 is as follows: respectively weigh silicone-modified acrylic resin, ECOAT waterborne polyurethane-modified alkyd resin, silica with a particle size of 1-5 μm, 1 g of defoamer, and 1.5 g of leveling agent, add the above components to 160 g of water, stir evenly, and obtain paper product coating.

[0039] Table 1 Addition amount of each component in the paper product coating provided in Preparation Examples 1-12 Preparation Example 13 Preparation Example 13 provides a paper product coating.

[0040] The difference between the above preparation example and preparation example 3 is that the particle size of silicon dioxide is 100-200 nm.

[0041] Preparation Example 14 Preparation Example 14 provides a paper product coating.

[0042] The difference between the above preparation example and preparation example 3 is that the particle size of silicon dioxide is 30-50 nm.

[0043] Preparation Example 15-23 Preparation Examples 15-23 each provide a paper product coating.

[0044] The difference between the above preparation example and preparation example 3 is that the silicon dioxide is compounded with three kinds of silicon dioxide with particle sizes of 1-5 μm, 100-200 nm and 30-50 nm, and the compounding ratio is shown in Table 2 below.

[0045] Table 2 Silica and weight ratio in paper product coatings provided by Preparation Examples 15-23 Preparation Example Weight ratio of silica with different particle sizes 15 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:1.5:2.5 16 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:1.8:2.5 17 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2:2.5 18 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2.3:2.5 19 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2.5:2.5 20 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2:2 21 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2:2.2 22 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2:2.8 23 The weight ratio of 1-5μm, 100-200nm and 30-50nm is 1:2:3 Comparative Preparation Example 1 Comparative Preparation Example 1 provides a paper product coating.

[0046] The difference between the comparative preparation example and preparation example 3 is that the organosilicon-modified acrylic resin is replaced by an equal amount of ECOAT waterborne polyurethane-modified alkyd resin.

[0047] Comparative Preparation Example 2 Comparative Preparation Example 2 provides a paper product coating.

[0048] The difference between the comparative preparation example and the preparation example 3 is that the ECOAT waterborne polyurethane modified alkyd resin is replaced by an equal amount of silicone modified acrylic resin.

[0049] Comparative Preparation Example 3 Comparative Preparation Example 3 provides a paper product coating.

[0050] The difference between the comparative preparation example and the preparation example 3 is that the addition amount of silicon dioxide is 0.

[0051] Examples 1-23 Examples 1-23 each provide a kind of white card paper.

[0052] The difference between the above embodiments is that the paper product coatings coated on the surface of the white cardboard are derived from Preparation Examples 1-23 respectively.

[0053] The preparation method of the white cardboard provided in Example 1-23 is as follows: firstly, a white cardboard base paper is prepared, and then the paper product coating is applied to the upper and lower surfaces of the white cardboard base paper, and the coating amount is 10 g / m 2 , dry to obtain white card paper.

[0054] Comparative Examples 1-3 Comparative Examples 1-3 provide a kind of white card paper respectively.

[0055] The difference between the comparative example and Example 3 is that the paper product coatings coated on the surface of the white cardboard are respectively derived from comparative preparation examples 1-3 Performance Test Various performance tests were performed on the white cardboard provided in Examples 1-23 and Comparative Examples 1-3, and the results are shown in Table 3 below. The test method is as follows: (1) Water absorption is carried out in accordance with GB / T 1540; (2) Oxygen permeability is tested in accordance with GB / T19789; (3) Transverse folding endurance was measured in accordance with GB / T457-2008 using the MIT instrument method with an initial tension of 9.8 N. (4) Anti-blocking property: Use a No. 0 wire rod to apply polyacrylic acid water-based varnish on white cardboard (apply on the coating side of the paper product) and dry it. Cut the white cardboard coated with water-based varnish into two 12cm×12cm test samples. Then, place one of the test samples (water-based varnish side facing up) on a glass plate in an oven, and drip 0.2mL of water on the water-based varnish surface of the test sample; cover the other test sample (water-based varnish side facing down) on the test sample with water dripping on the water-based varnish surface; place a glass plate on the test sample (water-based varnish side facing down), and place another 1kg block on the glass plate. Finally, dry in an oven at 60°C for 60 minutes, and observe the adhesion of the two test samples; the anti-blocking evaluation details are as follows: Excellent: The test sample slides off directly without any adhesion; Good: The test sample is sticky, and there is no paper tearing on the surface; Middle: The test sample surface is sticky and the surface is slightly torn; Poor: The test sample surface is severely adhered and the paper is torn in a large area.

[0056] Table 3 Test results of various properties of white cardboard provided by Examples 1-23 and Comparative Examples 1-3 According to the test results in Table 3, the water absorption of the white cardboard obtained in Examples 1-23 is 36.2-44.7 g / m 2, oxygen permeability is 1782-1867cc / m 2 ·24h·Pa, the transverse folding endurance is 80-93 times, and the anti-adhesion rating is excellent. Therefore, it is shown that the white cardboard provided by the present application has good air permeability, good folding endurance, and appropriate water absorption. The packaging material prepared by using the white cardboard has good anti-adhesion and can meet the use requirements of the packaging material.

[0057] The test results of Examples 1-9 and Comparative Examples 1-2 show that after the white cardboard is coated with the paper product coating containing silicone modified acrylic resin and ECOAT waterborne polyurethane modified alkyd resin in Examples 1-9, the water absorption of the obtained white cardboard is 36.2-44.7 g / m 2 , oxygen permeability is 1782-1867cc / m 2 ·24h·Pa, the transverse folding endurance is 80-84 times, and the anti-adhesion rating is excellent; while in Comparative Example 1-2, after the white cardboard is coated with the paper product coating containing silicone modified acrylic resin or ECOAT waterborne polyurethane modified alkyd resin, the water absorption of the obtained white cardboard is 24.6-29.8g / m 2 , oxygen permeability is 1634-1657cc / m 2 ·24h·Pa, the transverse folding endurance is 71-75 times, and the anti-adhesion rating is medium, indicating that the paper product coating prepared by compounding the silicone-modified acrylic resin and the ECOAT waterborne polyurethane-modified alkyd resin has good air permeability and suitable water absorption; further comparison shows that the water absorption of the white cardboard obtained in Examples 2-4 and Examples 7-8 is 37.2-41.8g / m 2 , oxygen permeability is 1806-1852cc / m 2 24h Pa (≥1800cc / m 2 ·24h·Pa), indicating that the application further controls the addition amount of silicone-modified acrylic resin and ECOAT waterborne polyurethane-modified alkyd resin within the following range: 35-45 parts of silicone-modified acrylic resin and 13-18 parts of ECOAT waterborne polyurethane-modified alkyd resin, and the obtained paper product coating has better comprehensive performance in air permeability and water absorption.

[0058] The test results of Example 3, Example 10-12 and Comparative Example 3 show that after the white cardboard is coated with the paper product coating containing silicon dioxide in Example 3 and Example 10-12, the water absorption of the white cardboard is 40.5-42.3 g / m 2 , oxygen permeability is 1815-1844cc / m 2 ·24h·Pa, the transverse folding endurance is 82-84 times, and the anti-adhesion rating is excellent; while in comparative example 3, after the white cardboard is coated with a paper product coating without silicon dioxide, the water absorption of the white cardboard is 49.3g / m2 , oxygen permeability is 1583cc / m 2 ·24h·Pa, its air permeability and waterproofness are poor. Therefore, it is explained that the present application uses a paper product coating containing silicon dioxide to coat white cardboard, which can improve the air permeability and water absorption of white cardboard, and can make the white cardboard after printing and glazing less likely to stick in a humid environment.

[0059] From the test results of Example 3 and Examples 13-23, it can be seen that after Example 3 and Examples 13-14 use paper product coatings containing silicon dioxide of a single particle size to coat white cardboard, the transverse folding resistance of the white cardboard is 84 times; while after Examples 15-23 use paper product coatings containing 1-5μm silicon dioxide, 100-200nm silicon dioxide and 30-50nm silicon dioxide to coat white cardboard, the transverse folding resistance of the white cardboard is 85-93 times; further comparison shows that the transverse folding resistance of the white cardboard obtained in Examples 16-18 and Examples 21-22 is 90-93 times (≥90 times). Therefore, it is explained that the present application uses 1-5μm silicon dioxide, 100-200nm silicon dioxide and 30-50nm silicon dioxide for compounding, and the folding resistance of the obtained paper product coating is better and can meet the use requirements of packaging materials.

[0060] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A paper product coating, characterized in that: The invention comprises the following components in parts by weight: 30-50 parts of organosilicon-modified acrylic resin, 10-20 parts of ECOAT waterborne polyurethane-modified alkyd resin, 3-10 parts of silicon dioxide, 1 part of defoaming agent, 1-2 parts of leveling agent and 150-170 parts of water.

2. The paper product coating according to claim 1, characterized in that: The paper product coating comprises the following components in parts by weight: 35-45 parts of organosilicon-modified acrylic resin, 13-18 parts of ECOAT waterborne polyurethane-modified alkyd resin, 5-8 parts of silicon dioxide, 1 part of defoamer, 1-2 parts of leveling agent and 150-170 parts of water.

3. The paper product coating according to claim 1, characterized in that: The silicon dioxide is a mixture of 1-5 μm silicon dioxide, 100-200 nm silicon dioxide and 30-50 nm silicon dioxide.

4. The paper product coating according to claim 3, characterized in that: The weight ratio of the 1-5 μm silicon dioxide, the 100-200 nm silicon dioxide and the 30-50 nm silicon dioxide is 1:(1.5-2.5):(2-3).

5. The paper product coating according to claim 3, characterized in that: The weight ratio of the 1-5 μm silicon dioxide, the 100-200 nm silicon dioxide and the 30-50 nm silicon dioxide is 1:(1.8-2.3):(2.2-2.8).

6. A white cardboard, characterized in that: The invention comprises a base paper layer and a coating formed on the surface of the base paper layer by the paper product coating according to any one of claims 1 to 6.

7. The white cardboard according to claim 6, characterized in that: The water absorption of the white cardboard is 35-45g / m 2 .

8. The white cardboard according to claim 6 or 7, characterized in that: The coating has a weight of 8-12 g / m 2 The basis weight of the base paper layer is 180-220 g / m 2 .

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