Natural veneer fading agent and fading process thereof

Abstract

The invention discloses a natural veneer fading agent and a fading process thereof, and a component A comprises the following components in parts by weight: 5-10 parts of a sulfite fading agent, 6-10 parts of soluble silicate and 100 parts of deionized water; the component B comprises the following components in parts by weight: 2-8 parts of carboxymethyl cellulose, 1-3 parts of acid protease, 5-15 parts of acetic acid, 2-15 parts of a surfactant and 100 parts of deionized water. The acid protease is added and can be matched with the carboxymethyl cellulose, permeation of the carboxymethyl cellulose in the veneer tissue is promoted, and the edge closing phenomenon is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of veneer treatment, in particular to a natural veneer discoloring agent and a discoloring process thereof. Background Art

[0002] In the fading treatment of materials such as wood, the traditional method often uses hydrogen peroxide as the main oxidant. Hydrogen peroxide can destroy pigment molecules through its strong oxidizing property to achieve the purpose of bleaching. However, this method faces multiple technical problems and limitations in practical application:

[0003] Easy to turn yellow: Products bleached with hydrogen peroxide, especially textiles and wood exposed to air, are prone to yellowing due to re-oxidation. This is mainly because after hydrogen peroxide bleaching, the residual hydrogen peroxide or by-products produced during the bleaching process react with oxygen in the air, causing the product color to change.

[0004] Damage to materials: Hydrogen peroxide, as a strong oxidant, has a certain destructive effect on the fiber and cell structure of wood. Long-term or excessive use will lead to a decrease in material strength and embrittlement.

[0005] Safety issues: Hydrogen peroxide is a dangerous substance with strong oxidizing and corrosive properties. Strict safety measures are required during storage and use. At the same time, harmful gases may be produced during the bleaching process of hydrogen peroxide, posing a threat to the environment and human health.

[0006] Limited bleaching depth: For thicker materials such as veneer, the bleaching depth of hydrogen peroxide is limited, and it is difficult to achieve the ideal bleaching effect.

[0007] Edge trimming problem: During the wood bleaching process, hydrogen peroxide can easily cause obvious edge trimming on the edge of the veneer, affecting the appearance quality of the product.

[0008] It can be seen that the prior art lacks a new veneer dyeing and fading agent and a fading process thereof, which makes the veneer fade deeper and has less edge trimming. Summary of the invention

[0009] 1. Technical issues to be solved

[0010] In view of the deficiencies of the prior art, the present invention provides a natural veneer discoloring agent and a discoloring process thereof, which solves the problems raised in the above-mentioned background technology.

[0011] (II) Technical solution

[0012] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0013] A natural veneer discoloring agent, comprising component A and component B;

[0014] The component A comprises the following components by weight: 5 to 10 parts of sulfite decolorizing agent, 6 to 10 parts of soluble silicate and 100 parts of deionized water;

[0015] The component B comprises the following components in parts by weight: 2-8 parts of carboxymethyl cellulose, 1-3 parts of acidic protease, 5-15 parts of acetic acid, 2-15 parts of surfactant and 100 parts of deionized water.

[0016] The sulfite discoloring agent is selected from one or more of sodium bisulfite, sodium pyrosulfite and sodium dithionite.

[0017] The soluble silicate is selected from one or more of sodium silicate, potassium silicate and ammonium silicate.

[0018] The ratio of the number of carboxymethyl groups to the number of cellulose units in the carboxymethyl cellulose molecule is 0.4-1.2.

[0019] The acidic protease is selected from one or more of acidic proline dipeptidase, acidic carboxypeptidase and Aspergillus niger fermentation protease.

[0020] The surfactant is selected from one or more of sodium lauryl sulfate, fatty alcohol polyoxyethylene ether, and polyethylene glycol fatty acid ester.

[0021] A veneer dyeing and fading process comprises the following steps:

[0022] Clean the veneer to ensure that the discolorant can fully contact the veneer surface;

[0023] Soaking treatment: soaking the natural veneer in the solution of component A and component B in claim 1 successively, with the soaking time being controlled at 5-15 hours and 5-30 hours respectively;

[0024] The discolorant is left on the veneer surface for a period of time so that it can fully penetrate and react with the dye in the veneer;

[0025] After the discolorant has fully reacted with the dye in the veneer, use clean water or a special cleaning agent to clean the discolorant residue on the surface of the veneer, and then let the veneer dry naturally or use drying equipment to accelerate the drying process.

[0026] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0027] The solution of the present invention has a deeper fading effect. Sulfite discoloring agents react with pigment groups (such as double bond structures) in wood to generate colorless or light-colored substances, thereby achieving a bleaching effect. However, the bleaching ability of sulfite discoloring agents is limited by their penetration ability and reaction rate. For thicker veneers, hydrogen peroxide may have difficulty in fully penetrating into the interior of the wood, resulting in insufficient bleaching depth. Adding soluble silicates to component A may assist hydrogen peroxide in better penetrating into the interior of the wood by increasing the permeability and stability of the solution. The colloidal structure formed by silicates in the solution helps to reduce the loss of sulfite discoloring agents and may promote their contact and reaction with wood pigments.

[0028] In the fading process of the solution of the present invention, the sulfite discoloring agent is easy to produce the edge of the wood veneer. This may be because the edge part is more fully in contact with hydrogen peroxide, or the wood structure of the edge part is looser, causing the sulfite discoloring agent to quickly decompose in this area and produce a bleaching effect. The carboxymethyl cellulose in the B component can react chemically with the wood veneer cellulose under acidic conditions, inhibiting the excessive concentration and rapid decomposition of the sulfite discoloring agent at the edge of the wood veneer, thereby reducing the edge-closing phenomenon. At the same time, the reacted carboxymethyl cellulose also helps to improve the uniform distribution and permeability of the discoloring agent on the wood surface, further improving the fading effect.

[0029] In addition, the acidic protease added in the present invention can cooperate with the carboxymethyl cellulose to promote the penetration of the carboxymethyl cellulose into the veneer tissue and reduce the edge closing phenomenon. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a photo obtained by fading the natural wood veneer in Example 1;

[0031] Figure 2 This is a photo obtained by fading the natural wood veneer in Example 2;

[0032] Figure 3 This is a photo obtained by fading the natural wood veneer in Example 3;

[0033] Figure 4 This is a photo obtained by fading the natural veneer in Comparative Example 1;

[0034] Figure 5 This is a photo of the natural wood veneer subjected to fading treatment in Comparative Example 2;

[0035] Figure 6 This is a photo obtained by fading the natural veneer in Comparative Example 3;

[0036] Figure 7 This is a photo obtained by fading the natural veneer in Comparative Example 4. DETAILED DESCRIPTION

[0037] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The present invention provides an efficient and environmentally friendly veneer dyeing and discoloring agent and its use process, which is suitable for scenes where it is necessary to remove or reduce the staining marks on the veneer surface, such as post-processing processes in furniture manufacturing, decorative materials and other industries. The following is a detailed description of the solution and its use process:

[0039] Composition of wood veneer staining and fading agent

[0040] Component A

[0041] Sulfite discolorants: 5-10 parts, choose one of sodium bisulfite, sodium pyrosulfite, sodium dithionite or a mixture. This type of discolorant can destroy the molecular structure of the dye through its reducing property, thereby achieving a fading effect. Compared with the oxidation reaction, the reduction reaction can maintain the stability of the veneer structure and reduce the edge.

[0042] Soluble silicate: 6-10 parts, one or more of sodium silicate, potassium silicate, and ammonium silicate. Silicate not only enhances the stability of the solution, but also promotes the fading reaction to a certain extent, by increasing the permeability and stability of the solution to help hydrogen peroxide penetrate better into the wood. The colloidal structure formed by silicate in the solution helps to reduce the loss of sulfite fading agents and may promote their contact and reaction with wood pigments.

[0043] Deionized water: 100 parts, used as solvent to ensure uniform mixing of components.

[0044] Component B

[0045] Carboxymethyl cellulose: 2-8 parts, the ratio of carboxymethyl groups to cellulose units in the molecule is 0.4-1.2. Carboxymethyl cellulose can react chemically with cellulose in the wood veneer under acidic conditions, inhibiting the excessive concentration and rapid decomposition of sulfite-based discolorants at the edge of the wood veneer, thereby reducing the edge closing phenomenon. At the same time, the reacted carboxymethyl cellulose also helps to improve the uniform distribution and permeability of the discolorant on the wood surface, further improving the discoloration effect.

[0046] Acidic protease: 1-3 parts, acidic proline dipeptidase, acidic carboxypeptidase, Aspergillus niger fermentation protease, etc. are selected to accelerate the degradation of protein molecules in the veneer through enzymatic hydrolysis, which is conducive to the chemical reaction between carboxymethyl cellulose and veneer cellulose under acidic conditions, further reducing the edge closing phenomenon.

[0047] Acetic acid: 5-15 parts, to adjust the pH value of the solution and optimize the enzymatic reaction conditions.

[0048] Surfactant: 2-15 parts, sodium lauryl sulfate, fatty alcohol polyoxyethylene ether, polyethylene glycol fatty acid ester, etc. are selected to improve the wettability and permeability of the decolorizing agent on the veneer surface.

[0049] Deionized water: 100 parts, also used as solvent.

[0050] Veneer dyeing and fading process

[0051] Cleaning: First, clean the veneer thoroughly to remove dust, grease and other impurities on the surface, and ensure that the discolorant can directly and fully contact the veneer surface. You can use a soft cloth, brush or high-pressure water gun to clean it.

[0052] Soaking treatment: Soak the natural veneer in the solution of component A and component B successively, and the soaking time is controlled at 5-15 hours and 5-30 hours respectively, so that the components can quickly penetrate into the interior of the veneer.

[0053] Stand and react: Take out the soaked veneer and place it in a ventilated place for a while (the specific time depends on the type of veneer, the degree of dyeing and the concentration of the discoloring agent) to allow the discoloring agent to fully react with the dyeing substances in the veneer. During this period, the veneer can be gently turned over to promote uniform reaction.

[0054] Cleaning and drying: After the discolorant and veneer material have fully reacted, use clean water or a special cleaning agent to thoroughly clean the veneer surface to remove the residual discolorant and other impurities. After cleaning, let the veneer dry naturally or use drying equipment to accelerate the drying process.

[0055] Through the above steps, the staining marks on the veneer surface can be effectively removed or reduced, and its original color and texture can be restored. This solution has the advantages of simple operation, significant effect, environmental protection and no pollution, and is suitable for the fading treatment of various veneer materials.

[0056] In the following examples and comparative examples, unless otherwise specified, the raw materials are commercially available. Parts are by weight.

[0057] Example 1

[0058] A natural veneer discoloring agent, comprising component A and component B;

[0059] The component A comprises the following components in parts by weight: 5 parts of sodium dithionite, 6 parts of sodium silicate and 100 parts of deionized water;

[0060] The component B comprises the following components in parts by weight: 2 parts of carboxymethyl cellulose, 3 parts of acidic protease, 5 parts of acetic acid, 15 parts of sodium lauryl sulfate and 100 parts of deionized water.

[0061] Example 2

[0062] A natural veneer discoloring agent, comprising component A and component B;

[0063] The component A comprises the following components in parts by weight: 7 parts of sodium dithionite, 8 parts of sodium silicate and 100 parts of deionized water;

[0064] The component B comprises the following components in parts by weight: 8 parts of carboxymethyl cellulose, 2 parts of acidic protease, 15 parts of acetic acid, 10 parts of sodium lauryl sulfate and 100 parts of deionized water.

[0065] Example 3

[0066] A natural veneer discoloring agent, comprising component A and component B;

[0067] The component A comprises the following components in parts by weight: 10 parts of sodium dithionite, 10 parts of sodium silicate and 100 parts of deionized water;

[0068] The component B comprises the following components in parts by weight: 6 parts of carboxymethyl cellulose, 1 part of acidic protease, 10 parts of acetic acid, 2 parts of sodium lauryl sulfate and 100 parts of deionized water.

[0069] Comparative Example 1: The difference from Example 1 is that only component A without adding 6 parts of sodium silicate is used for the decolorization treatment.

[0070] Comparative Example 2: The difference from Example 1 is that 2 parts of carboxymethyl cellulose are not added, but 2 parts of hydroxyethyl methyl cellulose are added instead.

[0071] Comparative Example 3: The difference from Example 1 is that 3 parts of acid protease are not added.

[0072] Comparative Example 4: The difference from Example 1 is that hydrogen peroxide is directly used for fading treatment.

[0073] In the above embodiment, the veneer treated with fading is natural veneer, and the immersion time of components A and B is 10 hours and 20 hours respectively. Carboxymethyl cellulose is purchased from Hebei Chaoyan, model IL6, substitution degree 0.6-0.7. Hydroxyethyl methyl cellulose: purchased from Huada Chemical, HEMC LH55RR, acid protease is purchased from industrial grade acid protease of Hebei Jiuyu Biotechnology Co., Ltd., enzyme activity 10000.

[0074] Measurement of fade depth

[0075] After cutting the surface with a utility knife, the cross section of the veneer is exposed and the depth of fading is measured using a vernier caliper.

[0076] The performance test results of the embodiments and comparative examples are shown in Table 1:

[0077] Table 1

[0078]

[0079]

[0080] It can be seen from the above experiments that the use of the formula of the present invention, especially the use of sodium silicate, greatly enhances the fading ability, and the use of carboxymethyl cellulose and acid protease greatly reduces the edge finishing situation.

[0081] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. Natural veneer discoloring agent, characterized by: It includes component A and component B; The component A comprises the following components in parts by weight: 5-10 parts of sulfite decolorizing agent, 6-10 parts of soluble silicate and 100 parts of deionized water; The component B comprises the following components in parts by weight: 2-8 parts of carboxymethyl cellulose, 1-3 parts of acidic protease, 5-15 parts of acetic acid, 2-15 parts of surfactant and 100 parts of deionized water.

2. The natural veneer discoloring agent according to claim 1, characterized in that: The sulfite discoloring agent is selected from one or more of sodium bisulfite, sodium pyrosulfite and sodium dithionite.

3. The natural veneer discoloring agent according to claim 1, characterized in that: The soluble silicate is selected from one or more of sodium silicate, potassium silicate and ammonium silicate.

4. The natural wood veneer discoloring agent according to claim 1, characterized in that: The ratio of the number of carboxymethyl groups to the number of cellulose units in the carboxymethyl cellulose molecule is 0.4-1.

2.

5. The natural veneer discoloring agent according to claim 1, characterized in that: The acidic protease is selected from one or more of acidic proline dipeptidase, acidic carboxypeptidase and Aspergillus niger fermentation protease.

6. The natural wood veneer discoloring agent according to claim 1, characterized in that: The surfactant is selected from one or more of sodium lauryl sulfate, fatty alcohol polyoxyethylene ether, and polyethylene glycol fatty acid ester.

7. A veneer dyeing and fading process, characterized in that: The process comprises the following steps: Clean the veneer; Soaking treatment: soaking the natural veneer in the solution of component A and component B in claim 1 successively, with the soaking time being controlled at 5-15 hours and 5-30 hours respectively; After the discoloring agent has fully reacted with the dye in the veneer, use clean water or a special cleaning agent to clean the discoloring agent residue on the surface of the veneer, and then let the veneer dry naturally or use a drying equipment to accelerate the drying process to obtain the faded veneer.

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