A production method for producing particleboard using formaldehyde-free glue

Application Number : CN201510465451.7 Application Date: August 3, 2015

Publication Number: CN106393383A Publication Date: February 15, 2017

[Applicant] Wanhua Eco-Board Co., Ltd. [Address] No. 5, Xinghuo Street, Science and Technology Park, Changping District, Beijing 102200

[Inventor] Gao Youqing; Liu Zhigang

[Country and Province Code] 11

[Abstract] The present invention provides a method for producing particleboard using formaldehyde-free adhesive, which mainly includes the steps of preparing particles, applying glue, laying, pre-pressing, and post-processing. Specifically, MDI is used as the main adhesive, and sodium lignin sulfonate, polyvinyl alcohol, soybean glue, or starch glue is used as an auxiliary adhesive. Compared with the existing technology, the present invention has the following advantages: 1. It solves the problem of using aluminum pads or mesh belts to transport slabs when single-layer or multi-layer particleboard production lines use formaldehyde-free adhesive to produce boards. 2. It solves the problem of being unable to transport slabs when continuous flat-pressing production lines use formaldehyde-free adhesive to produce boards. 3. It eliminates the slab conveying equipment, reduces the lateral density deviation and thickness deviation of the product, and improves product quality and stability. 4. It reduces the thickness of the slab before hot pressing, shortens the product closing time, and improves production efficiency. 5. It reduces the product sanding thickness, increases the sanding line speed, and reduces product production costs.

[Sovereign Item] A method for producing particleboard using formaldehyde-free glue, comprising the steps of particle preparation, gluing, laying, pre-pressing, hot pressing, and post-processing. The method is characterized by: particle preparation: After wood is chipped, it is processed into particles using equipment such as a flaker and a ring grinder. The particles are then separated into surface particles and core particles based on their shape and size. Particle drying: Based on production process requirements, the moisture content of the surface particles is controlled within 3-10% (preferably 5-7%, more preferably 6%); the moisture content of the core particles is controlled within 2-9% (preferably 4-6%, more preferably 4.5%). Gluing: The primary adhesive, MDI, is first applied to meet the required bonding strength of the board. The main adhesive applied to the surface layer is 3.5-6.5% (preferably 5-6%, more preferably 5.5%) of the surface wood shavings' weight, and the main adhesive applied to the core layer is 3.0-5.5% (preferably 3.8-4.8%, more preferably 4.4%) of the wood shavings' weight. Auxiliary adhesives (specifically, biomass adhesives such as polyvinyl alcohol, sodium lignin sulfonate, soy glue, and starch glue) are applied again to enhance the slab's wet strength and meet the slab's conveying requirements during board production. The auxiliary adhesive is applied at a ratio of 5-20% (preferably 12-17%, more preferably 15%), with a concentration of 2-40%. The paving step involves paving the surface and core wood shavings after the adhesive has been applied. The surface wood shavings are applied to both surface layers of the slab using a graded paving machine, with each surface layer weighing 50% of the surface wood shavings. The core wood shavings are applied to the core layer of the slab using a mechanical paving machine. Pre-pressing: The paved sheet is pre-pressed, and its pre-pressing compression rate is generally controlled at 30% to 80% (preferably 55 to 65%, more preferably 60%), and the rebound rate is 5 to 30% (preferably 8 to 15%, more preferably 10%). Hot pressing: The paved sheet is sent to a multi-layer flat press or a continuous flat press for hot pressing. The hot pressing temperature is 170 to 240°C (wherein the multi-layer flat press line is preferably 185 to 195°C; the continuous flat press line is preferably 210 to 220°C), the hot pressing pressure is 3 to 4 MPa (preferably 3.5 to 3.9 MPa, more preferably 3.7 MPa), and the hot pressing cycle is 6 to 20 seconds/mm (preferably 12 to 17 seconds/mm, more preferably 14 seconds/mm). Post-processing steps: The product is subjected to procedures such as cooling, trimming, cooling and homogenization, and sanding to complete the surface appearance quality treatment of the product.