Preparation method of novel formaldehyde-free impregnated membrane paper

Abstract

The invention discloses a preparation method of novel formaldehyde-free impregnated film paper, and relates to the technical field of impregnated film decorative paper.The preparation method comprises the following steps that 1, impregnating glue is prepared; step 2, gum dipping of the raw paper; and step 3, drying and rubberizing. According to the preparation of the novel formaldehyde-free impregnated membrane paper, the problem of formaldehyde residue caused by phenolic resin, urea resin or melamino-formaldehyde for traditional impregnated membrane paper is solved by utilizing the water-resistant acrylic acid modified polyvinyl acetate emulsion, and real formaldehyde-free treatment of a board product after facing and hot pressing is realized; according to the preparation of the novel formaldehyde-free impregnated membrane paper, polyvinyl acetate is modified by adding butyl acrylate and vinyl versatate, so that the water resistance of polyvinyl acetate is improved, the permeability of an impregnating adhesive solution to paper is improved, and the problem that the paper is easy to break due to non-uniform permeation of the adhesive solution of the paper is solved; meanwhile, the problem of poor water resistance caused by migration of small molecules due to external addition of a penetrant is also solved, and the water resistance and demolding performance of the impregnating adhesive are improved.

Description

Technical Field

[0001] The invention relates to the technical field of impregnated film decorative paper, in particular to a method for preparing novel formaldehyde-free impregnated film paper. Background Art

[0002] Impregnated paper, also known as impregnated paper, is an important decorative material with the advantages of excellent surface properties, beautiful and diverse patterns, low price, high temperature resistance and acid and alkali corrosion resistance. In the packaging industry, impregnated paper has become the preferred material for food packaging and pharmaceutical packaging due to its excellent physical and chemical properties such as water resistance and moisture resistance. In the building materials industry, impregnated paper is widely used in wall materials, floor materials and interior decoration due to its heat resistance, weather resistance and flame retardancy, and its market application is becoming more and more extensive.

[0003] At present, the production of impregnation mainly uses phenolic resin, urea-formaldehyde resin or melamine formaldehyde resin containing formaldehyde resin. Although the process technology has gradually matured after years of development, it still has many problems. Among them, the most prominent and urgent problem to be solved is the formaldehyde release problem. In order to reduce the free formaldehyde content and control costs, the modification of trialdehyde impregnating resin has also caused some new problems. In order to further reduce the indoor pollution caused by decorations and reduce the harm to consumers' health, new regulations on safety and environmental protection have been made in recent years. Therefore, the development of new formaldehyde-free impregnated film paper has great research significance and social value.

[0004] The formaldehyde-free impregnated film paper in the prior art mainly utilizes adhesives such as isocyanate, dipropylene phthalate, and polyvinyl acetate to replace formaldehyde-containing resin adhesives to produce formaldehyde-free impregnated film paper to achieve the purpose of formaldehyde-free and environmentally friendly. However, isocyanate adhesives have the characteristics of strong reactivity, must be stored separately in a sealed container, and the product has extremely strong bonding properties to various substances. The adhesive for impregnated paper must be a pre-polymerized mixture and must retain the activity for further reaction. It can only bond to the substrate but not to the steel plate. Dipropylene phthalate and polyvinyl acetate cannot meet the corresponding requirements in terms of water resistance or production efficiency, and the application technology needs to be improved.

[0005] The use of formaldehyde-free adhesives to prepare impregnated paper also has certain problems due to the process and supporting equipment. For example, when the raw paper is unrolled, it is immersed in the glue tank. If the penetration speed is not fast enough, the glue liquid on the paper will be uneven, and the paper will easily break when the machine is turned on and pulled. In addition, if the penetration speed is not fast enough, the problem can be solved by reducing the startup line speed and prolonging the contact time between the paper and the glue liquid to increase the permeability, which affects the production efficiency. If a penetrant is added externally, it is easy to cause small molecules to migrate, resulting in defects such as poor water resistance of the paper. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a novel formaldehyde-free impregnated film paper in order to solve the problems existing in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a novel formaldehyde-free impregnated film paper, comprising the following steps: Step 1: Prepare the impregnating glue: weigh the following raw materials by weight: 80-95 parts of modified polyvinyl acetate emulsion, 15-20 parts of mildew inhibitor, 5-10 parts of surfactant, 1-5 parts of chitosan, 2-6 parts of polyvinyl alcohol, 1-2 parts of sodium carboxymethyl cellulose and 1-2 parts of sodium polyacrylate, and the balance is deionized water; stir and mix evenly to obtain water-resistant modified polyvinyl acetate impregnating glue for later use.

[0008] Step 2: Base paper dipping: roll the prepared base paper onto the dipping machine, unroll and put the paper on the roller, spray water or steam to adjust the humidity after paper storage, and control the humidity at 15-45%; the base paper after humidity adjustment is conveyed through the dipping tank by the guide roller in the storage box, so that both sides of the base paper are immersed in the water-resistant modified polyvinyl acetate dipping glue, and the dipping time is 30-50 s; after being impregnated with the water-resistant modified polyvinyl acetate dipping glue, it is conveyed upward, and the excess dipping glue on both sides of the base paper is scraped off with a scraper to make the dipping thickness on both sides of the base paper uniform, so as to obtain the dipping base paper for standby use.

[0009] Step three is drying and gluing: the impregnated paper prepared in step two is dried in a segmented oven, and after being air-cooled to room temperature, the impregnated paper is coated with back glue on one side of the substrate and with surface glue on the other side to obtain the novel formaldehyde-free impregnated film paper.

[0010] When the novel formaldehyde-free impregnated film paper is used to prepare decorative panels, the side coated with the back adhesive is subjected to hot pressing to face the substrate, thereby completing the curing and bonding of the impregnated film paper and the substrate.

[0011] Preferably, the mildew inhibitor in step 1 is at least one of isothiazolinone, 2-(thiocyanatomethylmercapto)benzothiazole or 2-(2-hydroxyphenyl)-2-hydrogen-benzotriazole.

[0012] Preferably, the surfactant in step 1 is at least one of polyoxyethylene ester, fatty alcohol polyoxyethylene ether or polyether.

[0013] Preferably, the modified polyvinyl acetate emulsion described in step 1 is an acrylic acid modified polyvinyl acetate emulsion, which is prepared by the following method: adding polyvinyl alcohol, deionized water and emulsifier OP-10 to a reactor equipped with a stirrer, a condensing device and a temperature control system, heating, stirring and dissolving for 20 to 40 minutes; after cooling, adding vinyl acetate monomer and 15 to 45% of ammonium persulfate in total, stirring and dissolving at 90°C for 1 hour, and then cooling to 60°C; continuing to dropwise add the remaining vinyl acetate monomer, acrylic acid monomer and 15 to 45% of the initiator ammonium persulfate in total, stirring and mixing while adding, raising the temperature to 80 to 90°C and keeping the temperature, while adding the remaining ammonium persulfate, keeping the temperature for 0.5 to 1.5 hours, cooling to 60 to 80°C, adding citrate, and continuing to cool to 40°C to obtain the acrylic acid modified polyvinyl acetate emulsion. The addition amount of each component (the parts are by weight): 45-60 parts of deionized water, 350-450 parts of vinyl acetate monomer, 5-10 parts of acrylic acid monomer, 0.5-1.5 parts of ammonium persulfate, 5-10 parts of polyvinyl alcohol, 1-3 parts of OP-10, and 1.5-3 parts of citrate.

[0014] Preferably, the segmented oven described in step 3 is a four-stage oven, the temperature of each zone is T1 = 125-135 ° C, T2 = 140-150 ° C, T3 = 135-145 ° C, T4 = 120-130 ° C, the drying speed V = 15-20 m / min, the steam pressure P = 0.8-1.5 Mpa, and the wind speed H = 70-90 m 3 / min.

[0015] As a further solution of the present invention: the glue dipping machine includes a glue dipping pool, a movable frame is arranged above the glue dipping pool, a supporting roller is installed on the top of the glue dipping pool, a guide roller is arranged below the movable frame, a scraper is installed on the movable frame, the distribution gap of the scraper is adjusted by an adjusting mechanism, the height of the movable frame is adjusted by a lifting mechanism, the adjusting mechanism includes a rotating seat, the rotating seat is rotatably connected to the outer wall of the movable frame, the outer wall of the movable frame is fixedly connected to a fixed seat, one end of the rotating seat is fixedly connected to a first spur gear, the first spur gear is rotatably connected to the inside of the movable frame, the movable frame and the fixed seat are internally slidably connected with a toothed plate, the toothed plate and the first spur gear The top and bottom ends of the first threaded rod are fixedly connected to the rotating block, and the outer wall of the scraper is fixedly connected to the connecting plate, and the outer wall of the connecting plate is symmetrically provided with a positioning groove, and the outer wall of the rotating seat is provided with a connecting groove, and the inner wall of the rotating seat is symmetrically slidably connected with a positioning block extending to the inner cavity of the connecting groove, and the positioning block is provided with a semicircular surface at one end of the inner cavity of the connecting groove, and the first spring is connected between the positioning block and the rotating seat, and the outer wall of the positioning block is fixedly connected to a sliding rod extending from the rotating seat, and the outer wall of the movable frame is provided with a sliding groove and an arc groove, and the arc groove is located at one end of the sliding groove, and the sliding groove is for the sliding rod to slide.

[0016] As a further scheme of the present invention: the lifting mechanism includes a support seat, the support seat is symmetrically fixedly connected to both sides of the dipping pool, the top of the support seat is provided with a displacement groove, the inner wall of the displacement groove is slidably connected with a displacement frame, the displacement frame is fixedly connected to the movable frame, a motor is installed inside the support seat, the output end of the motor is connected with a second threaded rod, the second threaded rod extends to the inside of the displacement frame, the bottom of the movable frame is fixedly connected with a docking block, the outer wall of the docking block is provided with a slot, the two ends of the guide roller are fixedly connected with a plug rod, the top of the plug rod is provided with a fixing slot, the inside of the displacement frame is slidably connected with an extrusion frame, the inside of the movable frame is located at the outer wall of the extrusion frame and is rotatably connected with a second spur gear, the inside of the movable frame is located at the outer wall of the second spur gear and is slidably connected with a fixing rod extending to the top of the inner wall of the slot, a second spring is connected between the fixing rod and the movable frame, and the outer wall of the extrusion frame is fixedly connected with a reinforcement frame extending from the displacement frame.

[0017] As a further solution of the present invention: the outer wall of the tooth plate is provided with a first tooth groove, the first tooth groove is meshed with the first spur gear, and the outer wall of the tooth plate is provided with a first threaded hole, the first threaded hole matches the first threaded rod.

[0018] As a further solution of the present invention: the inner wall of the positioning groove is in contact with the outer wall of the positioning block, and the outer wall of one end of the sliding rod is in contact with the inner wall of the sliding groove.

[0019] As a further solution of the present invention: the inner wall of the displacement groove fits with the outer wall of the displacement frame, a second threaded hole is opened at the bottom end of the displacement frame, the second threaded hole matches the second threaded rod, the inner wall of the slot fits with the outer wall of the insertion rod, the inner wall of the fixing groove fits with the outer wall of the fixing rod, the outer walls of the extrusion frame and the fixing rod are both provided with second tooth grooves, and the second tooth grooves are meshed with the second spur gear.

[0020] As a further solution of the present invention: a slot is provided on the outer wall of the rotating block, and one end of the reinforcement frame is engaged with the slot.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. The preparation of the novel formaldehyde-free impregnated film paper of the present invention uses water-resistant acrylic modified polyvinyl acetate emulsion to solve the formaldehyde residue problem caused by phenolic resin, urea-formaldehyde resin or melamine formaldehyde used in traditional impregnated film paper, and the board product after hot pressing of the facing is truly formaldehyde-free; 2. The preparation of the novel formaldehyde-free impregnated film paper of the present invention improves its water resistance and the permeability of the impregnated glue solution to the paper by adding butyl acrylate and tert-butyl vinyl acetate, thereby solving the problem that the paper is easily broken due to uneven penetration of the glue solution; at the same time, it also solves the problem of poor water resistance caused by the migration of small molecules caused by the externally added penetrant, thereby improving the waterproofness and demoulding performance of the impregnated glue; 3. The preparation of the novel formaldehyde-free impregnated film paper of the present invention has a simple production process and is easy to operate. The obtained novel formaldehyde-free impregnated film paper can be stored for a long time after drying. The board obtained after hot pressing of the facing has high bonding strength, good scratch resistance, wear resistance, high temperature resistance and waterproofness; 4. The glue dipping machine of the present invention is provided with an adjustment mechanism, wherein the rotating block drives the first threaded rod to rotate, the first threaded rod drives the tooth plate to move, the tooth plate moves to rotate the first straight gear, the first straight gear drives the rotating seat to rotate, the rotating seat drives the scraper to move, so that the distance between the two scrapers can be adjusted, thereby adjusting the thickness of the glue dipping on the base paper; at the same time, the scraper can be quickly replaced and disassembled for cleaning; 5. The glue dipping machine described in the present invention is provided with a lifting mechanism. The operation of the motor drives the second threaded rod to rotate. The rotation of the second threaded rod drives the displacement frame to slide in the displacement groove, thereby adjusting the height of the movable frame; the insertion rod is inserted into the slot to install the guide roller. When the displacement frame moves to the bottom end of the displacement groove, the fixed rod is displaced and inserted into the fixed groove to fix the insertion rod, thereby fixing the guide roller, facilitating rapid installation and disassembly of the guide roller, and preventing the guide roller from loosening during use; at the same time, the displacement of the reinforcement frame is engaged with the rotating block, thereby fixing the rotating block, and then fixing the angle of the scraper, thereby preventing the scraper from loosening during use and affecting the glue dipping effect on the base paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the glue dipping machine of the present invention; Figure 2 It is a structural schematic diagram of the movable frame of the glue dipping machine of the present invention; Figure 3 It is a schematic diagram of the installation of the rotating seat of the dipping machine of the present invention; Figure 4 It is a schematic diagram of the installation of the tooth plate of the dipping machine of the present invention; Figure 5 It is a schematic diagram of the installation of the first threaded rod of the dipping machine of the present invention; Figure 6 It is a cross-sectional view of the rotating seat of the glue dipping machine of the present invention; Figure 7 It is a structural schematic diagram of the arc groove of the glue dipping machine of the present invention; Figure 8 This is a schematic diagram of the installation of the guide roller of the dipping machine of the present invention; Fig. 9 It is a structural schematic diagram of the insertion rod of the glue dipping machine of the present invention; Fig.10 It is a schematic diagram of the installation of the extrusion frame of the dipping machine of the present invention; Fig.11 For the glue dipping machine of the present invention Fig.10 Enlarged view of point A in the middle.

[0023] In the figure: 1. Glue dipping tank; 2. movable frame; 3. support roller; 4. guide roller; 5. scraper; 6. adjustment mechanism; 601. rotating seat; 602. fixed seat; 603. first straight gear; 604. tooth plate; 605. first threaded rod; 606. rotating block; 607. connecting plate; 608. positioning groove; 609. connecting groove; 610. positioning block; 611. first spring; 612. sliding rod; 613. sliding groove; 614. arc groove; 7. lifting mechanism; 701. supporting seat; 702. displacement groove; 703. displacement frame; 704. motor; 705. second threaded rod; 706. docking block; 707. slot; 708. insertion rod; 709. fixed groove; 710. extrusion frame; 711. second straight gear; 712. fixed rod; 713. second spring; 714. reinforcement frame. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is an explanation of an embodiment of the present invention based on the overall structure of the present invention.

[0026] Example 1: Preparation of a novel formaldehyde-free impregnated film paper Step 1: Prepare the impregnation glue: weigh the following raw materials in parts by weight: 80 parts of acrylic acid modified polyvinyl acetate emulsion, 15 parts of isothiazolinone, 5 parts of polyoxyethylene ester, 1 part of chitosan, 2 parts of polyvinyl alcohol, 1 part of sodium carboxymethyl cellulose and 1 part of sodium polyacrylate, and the balance is deionized water; stir and mix evenly to obtain the water-resistant modified polyvinyl acetate impregnation glue, which is set aside.

[0027] The acrylic acid modified polyvinyl acetate emulsion is prepared by the following method: adding polyvinyl alcohol, deionized water and emulsifier OP-10 to a reaction kettle equipped with a stirrer, a condensing device and a temperature control system, heating, stirring and dissolving for 20 minutes; after cooling, adding vinyl acetate monomer and ammonium persulfate accounting for 15% of the total amount, stirring and dissolving at 90°C for 1 hour, and then cooling to 60°C; continuing to drop the remaining vinyl acetate monomer, acrylic acid monomer and initiator ammonium persulfate accounting for 45% of the total amount, stirring and mixing while adding, heating to 80-90°C and keeping the temperature, while adding the remaining 40% of ammonium persulfate, keeping the temperature for 0.5 hours, cooling to 60°C, adding citrate, and continuing to cool to 40°C to obtain the acrylic acid modified polyvinyl acetate emulsion. The added amount of each component (the parts are in parts by weight): 45 parts of deionized water, 400 parts of vinyl acetate monomer, 5 parts of acrylic acid monomer, 0.5 parts of ammonium persulfate, 5 parts of polyvinyl alcohol, 1 part of OP-10, and 1.5 parts of citrate.

[0028] Step 2: Base paper dipping: roll the prepared base paper onto the dipping machine, unroll and put the paper on the roller, spray water to adjust the humidity after paper storage, and control the humidity at 25%; the base paper after humidity adjustment is conveyed through the dipping tank by the guide roller in the storage box, so that both sides of the base paper are immersed in the water-resistant modified polyvinyl acetate dipping glue, and the dipping time is 30s; after being impregnated with the water-resistant modified polyvinyl acetate dipping glue, it is conveyed upward, and the excess dipping glue on both sides of the base paper is scraped off with a scraper to make the dipping thickness on both sides of the base paper uniform, so as to obtain the dipping base paper for use.

[0029] Step 3 Drying and pasting: Dry the impregnated paper prepared in step 2 in a four-stage oven. The temperature of each zone is T1 = 125 ° C, T2 = 140 ° C, T3 = 135 ° C, T4 = 120 ° C, the drying speed is V = 15 m / min, the steam pressure is P = 0.8 Mpa, and the wind speed is H = 70-m 3 After the dried impregnated paper is cooled to room temperature by air, the back-coating adhesive is coated on the side of the paper close to the substrate, and the surface adhesive is coated on the other side to obtain the novel formaldehyde-free impregnated film paper.

[0030] Please refer to Figures 1 to 11The glue dipping machine includes a glue dipping pool 1, a movable frame 2 is arranged above the glue dipping pool 1, a supporting roller 3 is installed on the top of the glue dipping pool 1, a guide roller 4 is arranged below the movable frame 2, a scraper 5 is installed on the movable frame 2, the distribution gap of the scraper 5 is adjusted by an adjusting mechanism 6, and the height of the movable frame 2 is adjusted by a lifting mechanism 7. The adjusting mechanism 6 includes a rotating seat 601, the rotating seat 601 is rotatably connected to the outer wall of the movable frame 2, the outer wall of the movable frame 2 is fixedly connected to a fixed seat 602, one end of the rotating seat 601 is fixedly connected to a first straight gear 603, the first straight gear 603 is rotatably connected to the inside of the movable frame 2, the movable frame 2 and the fixed seat 602 are internally slidably connected with a tooth plate 604, the tooth plate 604 is in contact with the first straight gear 603, and the fixed seat 602 is internally rotatably connected with a tooth plate that runs through the tooth plate The first threaded rod 605 of 604, the top and bottom ends of the first threaded rod 605 are fixedly connected with a rotating block 606, the outer wall of the scraper 5 is fixedly connected with a connecting plate 607, the outer wall of the connecting plate 607 is symmetrically provided with positioning grooves 608, the outer wall of the rotating seat 601 is provided with a connecting groove 609, the interior of the rotating seat 601 is symmetrically slidably connected with a positioning block 610 extending to the inner cavity of the connecting groove 609, the positioning block 610 is located at one end of the inner cavity of the connecting groove 609 and is provided with a semicircular surface, a first spring 611 is connected between the positioning block 610 and the rotating seat 601, the outer wall of the positioning block 610 is fixedly connected with a sliding rod 612 extending from the rotating seat 601, the outer wall of the movable frame 2 is provided with a sliding groove 613 and an arc groove 614, the arc groove 614 is located at one end of the sliding groove 613, and the sliding groove 613 is for the sliding rod 612 to slide.

[0031] In this embodiment: the base paper passes through between the two scrapers 5, and the scraper 5 scrapes off the excess glue on the outer wall of the base paper. When adjusting the gap between the two scrapers 5, the rotating block 606 is rotated, and the rotating block 606 rotates to drive the first threaded rod 605 to rotate, and the first threaded rod 605 rotates to drive the tooth plate 604 to move, and the tooth plate 604 moves to drive the first straight gear 603 to rotate, and the first straight gear 603 rotates to drive the rotating seat 601 to rotate, and the rotating seat 601 rotates to drive the scraper 5 to move, so as to adjust the distance between the two scrapers 5, thereby adjusting the thickness of the glue on the base paper; When the scraper 5 is replaced, the rotating seat 601 is rotated, and the slide bar 612 slides in the slide groove 613. When the slide bar 612 moves into the arc groove 614, the depth of the arc groove 614 is deeper than the slide groove 613, so that the positioning block 610 and the slide bar 612 have displacement space. At this time, the connecting plate 607 can be directly moved out of the connecting groove 609, and the semicircular surface of the positioning block 610 is forced to move out of the connecting groove 609. After replacing the scraper 5, the connecting plate 607 is inserted into the connecting groove 609. At this time, the positioning block 610 is engaged into the positioning groove 608 by the elastic force of the first spring 611, and then the rotating seat 601 is rotated to reset. At this time, the sliding rod 612 moves from the arc groove 614 into the sliding groove 613, and one end of the sliding rod 612 contacts the bottom end of the inner wall of the sliding groove 613, so that the positioning block 610 cannot move out of the positioning groove 608, thereby fixing the scraper 5 to prevent the scraper 5 from loosening, facilitating the rapid replacement of the scraper 5, and facilitating the disassembly and cleaning of the scraper 5.

[0032] Please refer to Figures 8 to 11 The lifting mechanism 7 includes a support seat 701, which is symmetrically fixedly connected to both sides of the dipping tank 1. A displacement groove 702 is provided at the top of the support seat 701. A displacement frame 703 is slidably connected to the inner wall of the displacement groove 702. The displacement frame 703 is fixedly connected to the movable frame 2. A motor 704 is installed inside the support seat 701. The output end of the motor 704 is connected to a second threaded rod 705. The second threaded rod 705 extends to the inside of the displacement frame 703. The bottom end of the movable frame 2 is fixedly connected to a docking block 706. The outer wall of the docking block 706 is provided with a slot 707. , both ends of the guide roller 4 are fixedly connected with an insertion rod 708, and a fixing groove 709 is opened at the top of the insertion rod 708, a displacement frame 703 is internally slidably connected with an extrusion frame 710, the interior of the movable frame 2 is located on the outer wall of the extrusion frame 710 and is rotatably connected with a second spur gear 711, the interior of the movable frame 2 is located on the outer wall of the second spur gear 711 and is slidably connected with a fixing rod 712 extending to the top of the inner wall of the slot 707, a second spring 713 is connected between the fixing rod 712 and the movable frame 2, and the outer wall of the extrusion frame 710 is fixedly connected with a reinforcement frame 714 extending from the displacement frame 703.

[0033] In this embodiment, when the height of the movable frame 2 is adjusted, the motor 704 is started, and the operation of the motor 704 drives the second threaded rod 705 to rotate, and the rotation of the second threaded rod 705 drives the displacement frame 703 to slide in the displacement groove 702, thereby adjusting the height of the movable frame 2; When installing the guide roller 4, the docking block 706 is located above the dipping tank 1 at this time, and the insertion rod 708 can be directly inserted into the slot 707 to install the guide roller 4. When dipping the base paper, the movable frame 2 moves downward to drive the guide roller 4 into the dipping tank 1. When the displacement frame 703 moves to the bottom end of the displacement groove 702, the extrusion frame 710 contacts the bottom end of the inner wall of the displacement groove 702 and is displaced by force. The displacement of the extrusion frame 710 drives the second spur gear 711 to rotate, and the rotation of the second spur gear 711 drives the fixing rod 712 to displace. The fixing rod 712 is displaced and inserted into the fixing groove 709 to fix the insertion rod 708, thereby fixing the guide roller 4 to prevent the guide roller 4 from loosening during use, facilitating the quick installation and disassembly of the guide roller 4, and preventing the guide roller 4 from loosening during use. When the displacement frame 703 is located at the bottom of the displacement groove 702, the extrusion frame 710 is displaced by force, and the displacement of the extrusion frame 710 drives the reinforcement frame 714 to displace. The displacement of the reinforcement frame 714 engages with the rotating block 606, thereby fixing the rotating block 606, and then fixing the angle of the scraper 5, preventing the scraper 5 from loosening during use and affecting the gluing effect on the base paper.

[0034] Please refer to Figures 2 to 7 A first tooth groove is formed on the outer wall of the tooth plate 604 , and the first tooth groove is meshed with the first spur gear 603 . A first threaded hole is formed on the outer wall of the tooth plate 604 , and the first threaded hole matches the first threaded rod 605 .

[0035] In this embodiment: the rotating block 606 is rotated, the rotating block 606 rotates to drive the first threaded rod 605 to rotate, the first threaded rod 605 rotates to drive the tooth plate 604 to move, the tooth plate 604 moves to drive the first spur gear 603 to rotate, and the first spur gear 603 rotates to drive the rotating seat 601 to rotate.

[0036] Please refer to Figures 2 to 7 The inner wall of the positioning groove 608 fits with the outer wall of the positioning block 610 , and the outer wall of one end of the sliding rod 612 fits with the inner wall of the sliding groove 613 .

[0037] In this embodiment: the connecting plate 607 is inserted into the connecting groove 609, at which time the positioning block 610 is engaged into the positioning groove 608 by the elastic force of the first spring 611, and then the rotating seat 601 is rotated to reset, at which time the slide rod 612 moves from the arc groove 614 into the slide groove 613, and one end of the slide rod 612 contacts the bottom end of the inner wall of the slide groove 613, so that the positioning block 610 cannot move out of the positioning groove 608, thereby fixing the scraper 5.

[0038] Please refer to Figures 8 to 11The inner wall of the displacement groove 702 fits with the outer wall of the displacement frame 703, a second threaded hole is opened at the bottom end of the displacement frame 703, the second threaded hole matches the second threaded rod 705, the inner wall of the slot 707 fits with the outer wall of the insertion rod 708, the inner wall of the fixing groove 709 fits with the outer wall of the fixing rod 712, the outer walls of the extrusion frame 710 and the fixing rod 712 are both provided with second tooth grooves, and the second tooth grooves are meshed with the second spur gear 711.

[0039] In this embodiment: the operation of the motor 704 drives the second threaded rod 705 to rotate, and the rotation of the second threaded rod 705 drives the displacement frame 703 to slide in the displacement groove 702, thereby adjusting the height of the movable frame 2; when the guide roller 4 is installed, the docking block 706 is located above the dipping tank 1, and the insertion rod 708 can be directly inserted into the slot 707 to install the guide roller 4. When the base paper is dipped in glue, the movable frame 2 moves downward, driving the guide roller 4 to enter the dipping tank 1. When the displacement frame 703 moves to the bottom end of the displacement groove 702, the extrusion frame 710 contacts the bottom end of the inner wall of the displacement groove 702 and is displaced by force. The displacement of the extrusion frame 710 drives the second spur gear 711 to rotate, and the rotation of the second spur gear 711 drives the fixing rod 712 to displace, and the fixing rod 712 is displaced and inserted into the fixing groove 709 to fix the insertion rod 708, thereby fixing the guide roller 4.

[0040] Please refer to Figures 8 to 11 A slot is formed on the outer wall of the rotating block 606, and one end of the reinforcing frame 714 is engaged with the slot.

[0041] In this embodiment, when the displacement frame 703 is located at the bottom of the displacement groove 702 , the extrusion frame 710 is displaced by force, and the displacement of the extrusion frame 710 drives the reinforcement frame 714 to displace, and the displacement of the reinforcement frame 714 engages with the rotating block 606 to fix the rotating block 606 .

[0042] Example 2: Preparation of a novel formaldehyde-free impregnated film paper Step 1: Prepare the impregnation glue: weigh the following raw materials by weight: 90 parts of acrylic acid modified polyvinyl acetate emulsion, 18 parts of 2-(thiocyanate methylmercapto)benzothiazole, 8 parts of fatty alcohol polyoxyethylene ether, 3 parts of chitosan, 4 parts of polyvinyl alcohol, 1.5 parts of sodium carboxymethyl cellulose and 1.5 parts of sodium polyacrylate, and the balance is deionized water; stir and mix evenly to obtain the water-resistant modified polyvinyl acetate impregnation glue for later use.

[0043] The modified polyvinyl acetate emulsion is prepared by the following method: adding polyvinyl alcohol, deionized water and emulsifier OP-10 to a reaction kettle equipped with a stirrer, a condensing device and a temperature control system, heating, stirring and dissolving for 30 minutes; after cooling, adding vinyl acetate monomer and ammonium persulfate accounting for 25% of the total amount, stirring and dissolving at 90°C for 1 hour, and then cooling to 60°C; continuing to drop the remaining vinyl acetate monomer, acrylic acid monomer and initiator ammonium persulfate accounting for 35% of the total amount, stirring and mixing while adding, heating to 85°C and keeping the temperature, while adding the remaining 40% of ammonium persulfate, keeping the temperature for 1.0 hour, cooling to 70°C, adding citrate, and continuing to cool to 40°C to obtain the acrylic acid modified polyvinyl acetate emulsion. The added amount of each component (the parts are by weight): 52.5 parts of deionized water, 350 parts of vinyl acetate monomer, 7.5 parts of acrylic acid monomer, 1.0 part of ammonium persulfate, 7.5 parts of polyvinyl alcohol, 2 parts of OP-10, and 2.3 parts of citrate.

[0044] Step 2: Base paper impregnation: roll the prepared base paper onto the impregnation machine, unroll and put the paper on the roller, and then steam humidify the paper after paper storage, and the humidity is controlled at 35%; the humidified base paper is conveyed through the impregnation pool by the guide roller in the storage box, so that both sides of the base paper are impregnated in the water-resistant modified polyvinyl acetate impregnation glue, and the impregnation time is 40 s; after impregnation with the water-resistant modified polyvinyl acetate impregnation glue, it is conveyed upward, and the excess impregnation glue on both sides of the base paper is scraped off with a scraper to make the impregnation thickness on both sides of the base paper uniform, so as to obtain the impregnated base paper for use.

[0045] Step 3 Drying and pasting: Dry the impregnated paper prepared in step 2 in a four-stage oven. The temperature of each zone is T1=130℃, T2=145℃, T3=140℃, T4=125℃, drying speed V=17m / min, steam pressure P=1.25Mpa, wind speed H=80m 3 After the dried impregnated paper is cooled to room temperature by air, the back-coating adhesive is coated on the side of the paper close to the substrate, and the surface adhesive is coated on the other side to obtain the novel formaldehyde-free impregnated film paper.

[0046] The dipping device and application method used in its preparation are the same as those in Example 1 and will not be described in detail here.

[0047] Example 3: Preparation of a novel formaldehyde-free impregnated film paper Step 1: Prepare the impregnation glue: weigh the following raw materials by weight: 95 parts of acrylic acid modified polyvinyl acetate emulsion, 20 parts of 2-(2-hydroxyphenyl)-2-hydrogen-benzotriazole, 10 parts of polyoxyethylene ester, 5 parts of chitosan, 6 parts of polyvinyl alcohol, 2 parts of sodium carboxymethyl cellulose and 2 parts of sodium polyacrylate, and the balance is deionized water; stir and mix evenly to obtain the water-resistant modified polyvinyl acetate impregnation glue for later use.

[0048] The acrylic acid modified polyvinyl acetate emulsion is prepared by the following method: adding polyvinyl alcohol, deionized water and emulsifier OP-10 to a reaction kettle equipped with a stirrer, a condensing device and a temperature control system, heating, stirring and dissolving for 40 minutes; after cooling, adding vinyl acetate monomer and ammonium persulfate accounting for 45% of the total amount, stirring and dissolving at 90°C for 1 hour, and then cooling to 60°C; continuing to drop the remaining vinyl acetate monomer, acrylic acid monomer and initiator ammonium persulfate accounting for 25% of the total amount, stirring and mixing while adding, heating to 80-90°C and keeping the temperature, while adding the remaining 30% of ammonium persulfate, keeping the temperature for 1.5 hours, cooling to 80°C, adding citrate, and continuing to cool to 40°C to obtain the acrylic acid modified polyvinyl acetate emulsion. The added amount of each component (the parts are in parts by weight): 60 parts of deionized water, 450 parts of vinyl acetate monomer, 10 parts of acrylic acid monomer, 1.5 parts of ammonium persulfate, 10 parts of polyvinyl alcohol, 3 parts of OP-10, and 3 parts of citrate.

[0049] Step 2: Base paper dipping: roll the prepared base paper onto the dipping machine, unroll and put the paper on the roller, spray water to adjust the humidity after paper storage, and control the humidity at 45%; the base paper after humidity adjustment is conveyed through the dipping tank by the guide roller in the storage box, so that both sides of the base paper are immersed in the water-resistant modified polyvinyl acetate dipping glue, and the dipping time is 50 s; after being impregnated with the water-resistant modified polyvinyl acetate dipping glue, it is conveyed upward, and the excess dipping glue on both sides of the base paper is scraped off with a scraper to make the dipping thickness on both sides of the base paper uniform, so as to obtain the dipping base paper for use.

[0050] Step 3 Drying and pasting: Dry the impregnated paper prepared in step 2 in a four-stage oven. The temperature of each zone is T1=135℃, T2=150℃, T3=145℃, T4=130℃, drying speed V=20m / min, steam pressure P=1.5Mpa, wind speed H=90m 3 After the dried impregnated paper is cooled to room temperature by air, the back-coating adhesive is coated on the side of the paper close to the substrate, and the surface adhesive is coated on the other side to obtain the novel formaldehyde-free impregnated film paper.

[0051] The dipping device and application method used in its preparation are the same as those in Example 1 and will not be described in detail here.

[0052] The new formaldehyde-free impregnated film paper prepared in Examples 1-3 and the traditional phenolic resin adhesive were respectively used as comparative examples and cured and bonded to the substrate, and the side coated with the back adhesive was hot pressed with the substrate to complete the curing and bonding of the impregnated film paper and the substrate. The surface properties of the impregnated paper after hot pressing and curing were tested, as shown in Table 1.

[0053] Table 1 Surface performance test results of impregnated paper after hot pressing

[0054] In summary, the board obtained by hot pressing the new formaldehyde-free impregnated film paper prepared by the present invention has high bonding strength, good scratch resistance, wear resistance, high temperature resistance and waterproofness.

[0055] What is described above 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. A method for preparing a novel formaldehyde-free impregnated film paper, characterized in that: The steps include: Step 1: Prepare the impregnation glue, weigh the following raw materials by weight: 80-95 parts of modified polyvinyl acetate emulsion, 15-20 parts of mildew inhibitor, 5-10 parts of surfactant, 1-5 parts of chitosan, 2-6 parts of polyvinyl alcohol, 1-2 parts of sodium carboxymethyl cellulose and 1-2 parts of sodium polyacrylate, and the balance is deionized water; stir and mix evenly to obtain modified polyvinyl acetate impregnation glue, which is set aside; Step 2: base paper dipping, roll the prepared base paper onto the dipping machine, unwind and connect the paper to the roller, spray water or steam to adjust humidity after paper storage, and control the humidity at 15-45%; the base paper after humidity adjustment is conveyed through the dipping tank by the guide roller in the storage box, so that both sides of the base paper are dipped in the modified polyvinyl acetate dipping glue, and the dipping time is 30-50 seconds; after being dipped in the water-resistant modified polyvinyl acetate dipping glue, it is conveyed upward, and the excess dipping glue on both sides of the base paper is scraped off with a scraper, so that the dipping thickness on both sides of the base paper is uniform, and the dipped base paper is obtained for standby use; Step three: drying and gluing. The impregnated paper prepared in step two is dried in a segmented oven. After being cooled to room temperature by air, the impregnated paper is coated with back glue on one side of the substrate and with surface glue on the other side to obtain the novel formaldehyde-free impregnated film paper.

2. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 1, characterized in that: The mildew inhibitor described in step 1 is at least one of isothiazolinone, 2-(thiocyanatomethylmercapto)benzothiazole or 2-(2-hydroxyphenyl)-2-hydrogen-benzotriazole; the surfactant is at least one of polyoxyethylene ester, fatty alcohol polyoxyethylene ether or polyether.

3. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 1, characterized in that: The modified polyvinyl acetate emulsion described in step 1 is an acrylic acid modified polyvinyl acetate emulsion, which is prepared by the following method: in a reaction kettle equipped with a stirrer, a condensing device, and a temperature control system, polyvinyl alcohol, deionized water, and an emulsifier OP-10 are added, the temperature is raised, and the mixture is stirred and dissolved for 20 to 40 minutes; after cooling, vinyl acetate monomer and 15 to 45% of ammonium persulfate in the total amount are added, and the mixture is stirred and dissolved at 90°C for 1 hour, and then the temperature is lowered to 60°C; the remaining vinyl acetate monomer, acrylic acid monomer, and 15 to 45% of the initiator ammonium persulfate in the total amount are continuously added dropwise, and after stirring and mixing evenly, the mixture is raised to 80 to 90°C and kept warm, and the remaining ammonium persulfate is added at the same time, and the mixture is kept warm for 0.5 to 1.5 hours. The temperature is then lowered to 60-80° C., citrate is added, and the temperature is further lowered to 40° C. to obtain the acrylic acid-modified polyvinyl acetate emulsion; the addition amount of each component is: 45-60 parts of deionized water, 350-450 parts of vinyl acetate monomer, 5-10 parts of acrylic acid monomer, 0.5-1.5 parts of ammonium persulfate, 5-10 parts of polyvinyl alcohol, 1-3 parts of OP-10, and 1.5-3 parts of citrate, and the parts are by weight.

4. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 1, characterized in that: The segmented oven described in step 3 is a four-stage oven, the temperature of each zone is T1 = 125 ~ 135 ° C, T2 = 140 ~ 150 ° C, T3 = 135 ~ 145 ° C, T4 = 120 ~ 130 ° C, the drying speed V = 15 ~ 20m / min, the steam pressure P = 0.8-1.5Mpa, the wind speed H = 70-90m 3 / min.

5. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 1, characterized in that: The glue dipping machine used in step 2 comprises a glue dipping pool (1), a movable frame (2) is arranged above the glue dipping pool (1), a support roller (3) is installed at the top of the glue dipping pool (1), a guide roller (4) is arranged below the movable frame (2), a scraper (5) is installed on the movable frame (2), the distribution gap of the scraper (5) is adjusted by an adjustment mechanism (6), the height of the movable frame (2) is adjusted by a lifting mechanism (7), the adjustment mechanism (6) comprises a rotating seat (601), the rotating The seat (601) is rotatably connected to the outer wall of the movable frame (2), the outer wall of the movable frame (2) is fixedly connected to the fixed seat (602), one end of the rotating seat (601) is fixedly connected to a first spur gear (603), the first spur gear (603) is rotatably connected to the inside of the movable frame (2), the movable frame (2) and the fixed seat (602) are internally slidably connected to a toothed plate (604), the toothed plate (604) is in contact with the first spur gear (603), and the fixed seat (602) is internally rotatably connected A first threaded rod (605) is provided which passes through the tooth plate (604); the top and bottom ends of the first threaded rod (605) are fixedly connected to rotating blocks (606); the outer wall of the scraper (5) is fixedly connected to a connecting plate (607); the outer wall of the connecting plate (607) is symmetrically provided with positioning grooves (608); the outer wall of the rotating seat (601) is provided with a connecting groove (609); the interior of the rotating seat (601) is symmetrically slidably connected to a positioning block (610) extending into the inner cavity of the connecting groove (609); the positioning block (610) 610) is provided with a semicircular surface at one end of the inner cavity of the connecting groove (609), a first spring (611) is connected between the positioning block (610) and the rotating seat (601), the outer wall of the positioning block (610) is fixedly connected with a sliding rod (612) extending from the rotating seat (601), and the outer wall of the movable frame (2) is provided with a sliding groove (613) and an arc groove (614), the arc groove (614) is located at one end of the sliding groove (613), and the sliding groove (613) allows the sliding rod (612) to slide.

6. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 5, characterized in that: The lifting mechanism (7) comprises a support seat (701), the support seat (701) is symmetrically fixedly connected to two sides of the dipping pool (1), a displacement groove (702) is provided at the top of the support seat (701), a displacement frame (703) is slidably connected to the inner wall of the displacement groove (702), the displacement frame (703) is fixedly connected to the movable frame (2), a motor (704) is installed inside the support seat (701), the output end of the motor (704) is connected to a second threaded rod (705), the second threaded rod (705) extends to the inside of the displacement frame (703), and a docking block (706) is fixedly connected to the bottom end of the movable frame (2), and a slot (707) is provided on the outer wall of the docking block (706). ), both ends of the guide roller (4) are fixedly connected with an insertion rod (708), a fixing groove (709) is provided at the top of the insertion rod (708), an extrusion frame (710) is slidably connected inside the displacement frame (703), a second spur gear (711) is rotatably connected inside the movable frame (2) and located on the outer wall of the extrusion frame (710), a fixing rod (712) extending to the top of the inner wall of the slot (707) is slidably connected inside the movable frame (2) and located on the outer wall of the second spur gear (711), a second spring (713) is connected between the fixing rod (712) and the movable frame (2), and a reinforcement frame (714) extending from the displacement frame (703) is fixedly connected to the outer wall of the extrusion frame (710).

7. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 5, characterized in that: The outer wall of the tooth plate (604) is provided with a first tooth groove, the first tooth groove meshes with the first spur gear (603), and the outer wall of the tooth plate (604) is provided with a first threaded hole, the first threaded hole matches the first threaded rod (605).

8. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 5, characterized in that: The inner wall of the positioning groove (608) fits with the outer wall of the positioning block (610), and the outer wall of one end of the sliding rod (612) fits with the inner wall of the sliding groove (613).

9. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 6, characterized in that: The inner wall of the displacement groove (702) fits with the outer wall of the displacement frame (703); a second threaded hole is provided at the bottom end of the displacement frame (703); the second threaded hole matches with the second threaded rod (705); the inner wall of the slot (707) fits with the outer wall of the insertion rod (708); the inner wall of the fixing groove (709) fits with the outer wall of the fixing rod (712); the outer walls of the extrusion frame (710) and the fixing rod (712) are both provided with second tooth grooves; the second tooth grooves mesh with the second spur gear (711).

10. The method for preparing a novel formaldehyde-free impregnated film paper according to claim 6, characterized in that: The outer wall of the rotating block (606) is provided with a slot, and one end of the reinforcing frame (714) is engaged with the slot.

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