A fruit packaging material and a method for manufacturing the same

Abstract

The application belongs to the field of papermaking packaging materials, and particularly discloses a fruit packaging material and a preparation method thereof. At least one of carbodiimide and polycarbodiimide is used as a crosslinking agent in a sizing combination, so that the wet strength and water resistance of the fruit packaging material paper can be improved, the paper aldehyde group residue can be avoided, the packaging material can be easily pulped, and the use requirements of the market can be met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of papermaking packaging materials, and particularly relates to a fruit packaging material and a preparation method thereof. BACKGROUND

[0002] With the rise of green and environmental protection concept, paper replacing plastic has begun to develop rapidly. Compared with traditional plastic fruit packaging bags, fruit packaging paper has the characteristics of green and environmental protection and is highly praised. Fruit bag packaging paper is mainly used for packaging picked fruits and is a kind of special paper with high wet strength and high water resistance, and the basis weight of the paper is generally 40-50 g / m 2 . In order to improve the wet strength and water resistance of the fruit bag packaging paper, a high proportion of long fiber pulp board is often added in the production process, resulting in an increase in cost. In order to improve the wet strength and water resistance, a large amount of wet strength agent needs to be added and a heavy sizing method needs to be used, which can cause the deposition of the production system to accumulate and easily lead to the generation of sludge and adhesive, thereby increasing the cleaning cost. Moreover, the wet strength agent is a thermosetting chemical agent, which can aggravate the difficulty of the disintegration of recycled paper with the extension of time and requires a higher disintegration equipment.

[0003] Therefore, there is still a need to develop a scheme capable of preparing paper with high wet strength and high water resistance while facilitating the disintegration and recycling of the paper. SUMMARY

[0004] In view of the defects involved in the prior art, the present application provides a fruit packaging material and a preparation method thereof.

[0005] To achieve the above-mentioned purpose, the technical scheme comprises the following:

[0006] A sizing composition comprises the following components in parts by weight: sizing starch 100 parts, sizing agent 5-15 parts, crosslinking agent 6-15 parts, and silica sol 0-15 parts, wherein the crosslinking agent comprises at least one of carbodiimide and polycarbodiimide.

[0007] The present application uses at least one of carbodiimide and polycarbodiimide as a crosslinking agent to perform crosslinking reaction with the carbonyl group of the carboxyl group in the sizing agent, but does not perform crosslinking with the hydroxyl group of the paper base, that is, selective crosslinking, which can improve the wet strength and water resistance of the fruit packaging material paper, and at the same time, can avoid the residual aldehyde group of the paper, the easy disintegration of the packaging material, and the meeting of the use demand of the market.

[0008] Preferably, the average particle size of the silica sol is 10-15 nm.

[0009] Preferably, the silica sol comprises at least one of ordinary silica sol and special silica sol, and the special silica sol comprises at least one of string-shaped silica sol and branched silica sol.

[0010] The film forming property of the silica sol further improves the water resistance of the packaging material, improves the printing property, the silica sol and the crosslinking agent synergistically improve the water resistance of the packaging material, and the special-shaped silica sol has lower surface free energy than the ordinary silica sol and can further improve the water resistance due to the cross-lapping during the drying and film forming process.

[0011] Preferably, the silica sol is 2-10 parts by weight.

[0012] Preferably, the sizing starch comprises corn oxidized starch.

[0013] Preferably, the sizing agent comprises a styrene-acrylic surface sizing agent, and the sizing agent is a compound synthesized from a carboxyl-containing styrene and acrylic acid.

[0014] The application also provides a preparation method of the fruit packaging material, comprising the following steps:

[0015] The sizing composition is applied to the paper, and then the paper is dried, polished and rolled to obtain the fruit packaging material.

[0016] The paper has no special requirements, and a conventional broadleaf forest, coniferous forest fiber paper can be used.

[0017] Preferably, the solid content of the sizing composition is 6-25 wt.%, the viscosity of the sizing composition is 30-100 mpa.s, and the pH is 4-9.

[0018] Preferably, the sizing amount of the sizing is 1.0-3.0 g / m 2 .

[0019] The fruit packaging material prepared by the preparation method of the fruit packaging material provided above is a paper packaging material, has excellent wet strength and water resistance, and is easy to be pulped during recycling, and is more environmentally friendly.

[0020] Compared with the prior art, the application has the following beneficial effects: the application uses at least one of carbodiimide and polycarbodiimide as a crosslinking agent to perform crosslinking reaction with the carbonyl group of the carboxyl group in the sizing agent, but does not perform crosslinking reaction with the hydroxyl group of the paper base, that is, selective crosslinking can improve the wet strength and water resistance of the fruit packaging material paper, meanwhile, can avoid the residual of the aldehyde group of the paper, the packaging material is easy to be pulped, and meets the use requirements of the market. DETAILED DESCRIPTION

[0021] In order to better illustrate the purpose, technical scheme and advantages of the application, the application will be further described below through specific examples. Unless otherwise specified, the test methods used in the examples and / or comparative examples are conventional methods; and the materials, reagents and the like used, unless otherwise specified, can be obtained from commercial channels.

[0022] Examples 1-4 and Comparative Examples 1-4

[0023] A method for preparing a fruit packaging material, comprising the following steps:

[0024] (1) A conventional bleached kraft pulp was formed in a wire part, and then dried in a pre-dryer after passing through a press part, to obtain a base paper; wherein, only in Comparative Example 1, a polyamide epichlorohydrin resin (PAE) wet strength agent was added to the bleached kraft pulp, and the amount was 10 kg / t of paper;

[0025] (2) The components were mixed uniformly in the feeding station of a size press according to the formulation in Table 1, to obtain a sizing composition;

[0026] (3) The sizing composition was transferred to a sizing part, and double-sided film transfer sizing was performed on the base paper, the solid content of the sizing agent was 20 wt.%, the viscosity was 50 mpa.s, the pH was 7.0, and the sizing amount was 2.5 g / m 2 ;

[0027] (4) After drying, calendering and winding, the fruit packaging material was obtained;

[0028] Part of the raw material information:

[0029] Corn oxidized starch: Foshan ZhenDong ZD-601;

[0030] Sizing agent: phenylpropyl surface sizing agent, Zhejiang Chuanhua HS-P;

[0031] Polycarbodiimide: Model XR-5580, commercially available;

[0032] Silica sol with branched chain: Model LZ-1, commercially available;

[0033] Common silica sol: Model SNOWTEX-N, commercially available.

[0034] Table 1

[0035]

[0036] Performance test:

[0037] The above prepared fruit bag packaging material was respectively subjected to wet strength, water resistance and disintegration test in an amount of 40 g / m 2 , and the test method was as follows, and the test results were as shown in Table 2:

[0038] (1) Wet strength: reference to GB / T 465.2-2008 paper and paperboard tensile strength after immersion for measurement;

[0039] (2) Water resistance: refer to the test of water absorption of paper and paperboard (Bristle method) according to GB / T 1540-2002

[0040] (3) Disintegration test: observe whether there are fiber agglomerations after 20000 rotations of a standard laboratory defibrator (L&W T-100).

[0041] Table 2

[0042] Group / property Wet tensile strength kN / m Absorbency g / m 2 ]] Disintegration difficulty Example 1 0.686 31.8 Easy (no lumps) Example 2 0.570 29.4 Easy (no lumps) Example 3 0.566 28.4 Easy (no lumps) Example 4 0.579 31.2 Easy (no lumps) Comparative Example 1 0.677 33.5 Difficult (large lumps) Comparative Example 2 0.216 28.6 Easy (no lumps) Comparative Example 3 0.341 28.9 Easy (no lumps) Comparative Example 4 0.467 36.5 Easy (small lumps)

[0043] As can be seen from Example 1 and Comparative Examples 1-4, the polycarbodiimide in the sizing composition of the present application, as a crosslinking agent, replaces the conventional glyoxal to crosslink with the carbonyl of the carboxyl in the conventional sizing agent, but does not crosslink with the hydroxyl of the paper base, i.e. selective crosslinking, which can improve the wet strength and water resistance of the fruit packaging material paper, and meanwhile, can avoid the residual aldehyde group of the paper and the easy disintegration of the packaging material; since the polycarbodiimide is only a polymer of carbodiimide, the inventors have also found that the carbodiimide, as a monomer to crosslink with the conventional sizing agent, can also improve the wet strength and water resistance of the fruit packaging material paper of the sizing composition, and the effect is similar. In addition, as can be seen from Comparative Example 3, if the amount of the polycarbodiimide is too small, the crosslinking effect is small, which is not enough to significantly improve the wet strength and water resistance of the packaging material paper, but if the amount is too large, the cost is high, and the degree of improvement of the wet strength and water resistance is not large, therefore, the amount of the polycarbodiimide is preferably 6-15 parts by weight, and more preferably 8-10 parts by weight.

[0044] As can be seen from Example 1 and Comparative Examples 2-4, after the addition of the silica sol, the crosslinking agent is used to react with the carbonyl of the carboxyl in the sizing agent, which can enhance the water resistance and wet strength of the paper surface, and then the film-forming property of the silica sol is used to further improve the water resistance and the printing performance, therefore, the silica sol and the polycarbodiimide can synergistically improve the water resistance of the packaging material, and as can be seen from Example 2 and 4, the branched silica sol has a lower surface free energy than the ordinary silica sol, and can further improve the water resistance due to the crosslinking of the branched silica sol during the drying process; the beaded silica sol has similar effects as the branched silica sol, and the effects of improving the water resistance of the packaging material are similar.

[0045] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, but not to limit the protection scope of the present application, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A sizing composition characterized in that, The composition comprises the following components by weight: sizing starch 100 parts, sizing agent 5-15 parts, crosslinking agent 6-15 parts, silica sol 0-15 parts, the crosslinking agent comprising at least one of carbodiimide, polycarbodiimide; the sizing agent being a compound synthesized from carboxyl-containing styrene and acrylic acid.

2. The sizing composition of claim 1, wherein, The silica sol comprises at least one of common silica sol, special silica sol, the special silica sol comprising at least one of string-shaped silica sol, branched-shaped silica sol; the average particle size of the silica sol being 10-15 nm.

3. The sizing composition of claim 1, wherein The silica sol is 2-10 parts by weight.

4. The sizing composition of claim 1, wherein The sizing starch comprises corn oxidized starch.

5. A method for producing a fruit packaging material, characterized by, The method comprises the following steps: The sizing composition of any one of claims 1-4 is applied to paper, and then the paper is dried, calendered and coiled to obtain the fruit packaging material.

6. The method for producing a fruit package material according to claim 5, characterized by, The sizing method is film transfer sizing method.

7. The method for producing a fruit package material according to claim 5, wherein The solid content of the sizing composition is 6-25 wt.%, the viscosity of the sizing composition is 30-100 mpa.s, and the pH is 4-9.

8. The method for producing a fruit package material according to claim 5, characterized by, The sizing amount of the sizing is 1.0-3.0 g / m 2 .

9. A fruit packaging material prepared by the method of any one of claims 5-8.

Images