Powdered glass fiber-reinforced phenol-formaldehyde adhesive mixture for the production of beech plywood with enhanced screw-withdrawal torque

Abstract

The use of woven glass fiber fabrics bonded between veneer layers has been shown to negatively affect the physical and mechanical properties of plywood due to the non-homogeneous distribution of the woven fibers. Moreover, bonding woven glass fibers requires increased adhesive consumption. Enhancing the strength properties and screw-withdrawal torque of plywood produced from various types of glass fibers and different wood species will improve the service life of the product, thereby providing economic benefits. The purpose of the present invention is to ensure homogeneity in the mixture of glass fibers and adhesive, reduce adhesive consumption, and increase the screw-withdrawal torque of beech plywood. In the invention, powdered glass fibers of different particle sizes are mixed with phenol-formaldehyde adhesive, and this adhesive mixture is applied homogeneously between beech veneer layers to produce plywood.

Description

[0001] SPECIFICATION

[0002] POWDERED GLASS FIBER-REINFORCED PHENOL-FORMALDEHYDE

[0003] ADHESIVE COMPOSITION FOR THE MANUFACTURE OF BEECH PLYWOOD WITH ENHANCED SCREW WITHDRAWAL TORQUE PERFORMANCE

[0004] TECHNICAL FIELD

[0005] The present invention relates to the forest products industry, and more specifically to the manufacturing of wood-based products and the furniture sector.

[0006] BACKGROUND OF THE INVENTION

[0007] In the known state of the art, studies have been conducted in which woven glass fiber fabrics are bonded between veneer layers. However, in such applications, the woven glass fiber inserted between the veneers does not disperse homogeneously across all veneer layers, thereby adversely affecting the physical and mechanical properties of the resulting plywood panels. Moreover, bonding woven glass fiber fabrics requires the use of a higher amount of adhesive.

[0008] In order to overcome the above-mentioned problems, there is a need in the technical field for the development of an invention that addresses these issues.

[0009] Studies to be conducted using different types of glass fibers and plywood manufactured from various wood species will enhance the strength properties and screw-withdrawal torque performance of the resulting materials, thereby increasing product service life and providing economic benefits. Additionally, such improvements contribute to the efficient and effective utilization of raw materials obtained from forest resources.

[0010] Screw-driving operations may cause injuries to the soft tissues of the musculoskeletal system associated with the upper-extremity muscles. Sudden and forceful screw insertion, as well as repetitive and static movements, may result in strain and damage in the hand, wrist, forearm, shoulder, and neck regions. Therefore, determining screw-withdrawal torque performance is of importance, as it provides guidance for minimizing these health risks. DESCRIPTION OF THE INVENTION

[0011] The purpose of the present invention is to ensure homogeneity in the mixture of glass fibers and adhesive, to reduce adhesive consumption, and to enhance the screw-withdrawal torque performance of beech plywood material. Within the scope of the invention, powdered glass fibers of various particle sizes are mixed with phenol-formaldehyde adhesive, and this adhesive mixture is applied homogeneously between beech veneer layers to produce the plywood.

[0012] The increasing number of industrial manufacturers and the resulting difficulty in accessing sufficient and high-quality raw materials cause significant challenges in the market. The invention will indirectly contribute to the efficient utilization of national forest resources and the optimal use of each harvested tree.

[0013] Description of the Figures

[0014] Figure 1. Seating torque test results

[0015] Figure 2. Maximum torque test results

[0016] DETAILED DESCRIPTION OF THE INVENTION

[0017] • In the present invention, plywood is produced by mixing powdered glass fibers of different particle sizes with phenol-formaldehyde adhesive and applying this adhesive mixture homogeneously between beech veneer layers. Detailed explanations of the invention, which enhances the screw-driving performance of beech plywood, are provided below.

[0018] • Beech rotary-cut veneers with a thickness of 2 mm and dimensions of 600 x 600 mm, obtained from beech logs in accordance with TS 1250 (1974), were procured in ready-to-use form.

[0019] • Mixtures of powdered glass fibers were prepared by weighing the fibers at ratios of 10%, 20%, and 30% using a precision balance and mixing them with phenolformaldehyde adhesive at corresponding ratios of 70%, 80%, and 90%, respectively. Adhesive mixtures were prepared separately for powdered glass fiber particle sizes of 10 pm and 25 pm. • The powdered glass fiber and phenol-formaldehyde adhesive, added to beakers at predetermined ratios, were blended using a mechanical mixer until a homogeneous mixture was obtained.

[0020] • Rulo ile kaplamalara %10, %20 ve %30 oranlannda iki farkli boyuttaki cam lifi ilave edilmig 200 g / m2tutkal surulmugtur.

[0021] • Tutkallanan papeller ile 7 katmanli levha taslaklan olugturulmugtur.

[0022] • 600x600 mm levha taslaklan tek katli hidrolik preste 120 °C pres sicakligmda 12 kg / cm2pres basmcmda 10 dakika preslenmigtir.

[0023] • Uretimi gergeklegtirilen levhalannm egit gartlarda soguyarak bigim degigikliklerinin dnune gegilebilmesi amaciyla 1 hafta suresince aralannda istif gitasi kullanilmaksizm ust uste istiflenerek ig ve dig katmanlan arasmdaki rutubet ve sicaklik farkl 111 klan m n giderilmesi saglanmigtir.

[0024] For screw-withdrawal torque performance tests, three different screwdrivers with torque ranges of 1-1.2 N m, 1.2-3.0 N m, and 3.0-6.0 N m were used.

[0025] • Test specimens measuring 500 x 50 mm were cut from the produced beech plywood panels in accordance with TS 1250 (1974).

[0026] • Guide holes with a diameter of 3.5 mm were drilled at 50 mm intervals using a column drill, with hole depths set to match the total thickness of the test specimens.

[0027] • Metal plates 10 mm thick with countersunk centers were placed on the specimens to facilitate screw-withdrawal torque testing.

[0028] • In the study, 4 x 30 mm steel wood screws with a Phillips head were used.

[0029] • The screws were inserted into the guide-drilled plywood test specimens using torque-controlled screwdrivers.

[0030] For screw-withdrawal torque performance tests, three different screwdrivers with torque ranges of 1-1.2 N m, 1.2-3.0 N m, and 3.0-6.0 N m were used.

[0031] Test specimens measuring 500 x 50 mm were cut from the produced beech plywood panels in accordance with TS 1250 (1974). Guide holes with a diameter of 3.5 mm were drilled at 50 mm intervals in the cut test specimens using a column drill, with the depth of the holes adjusted to match the total thickness of the specimens.

[0032] • For screw-withdrawal torque testing, metal plates 10 mm thick with a countersunk center were placed on top of the test specimens.

[0033] • In the study, 4 x 30 mm steel wood screws with a Phillips head were used.

[0034] • The screws were driven into the guide-drilled plywood test specimens using torque-controlled screwdrivers.

Claims

CLAIMS1 ) A mixture of powdered glass fiber-reinforced phenol-formaldehyde adhesive for the production of beech plywood with enhanced screw-withdrawal torque, characterized in that the adhesive and glass fiber mixture comprises powdered glass fibers at ratios of 10%-30% for fiber sizes of 10 pm and 25 pm, and phenol-formaldehyde adhesive at ratios of 70%-90% for the remainder of the glass fibers.2) The mixture according to claim 1 , characterized in that for 10 pm glass fibers, the mixture preferably comprises 20% powdered glass fiber and preferably 80% phenol-formaldehyde adhesive to achieve optimal seating torque.3) The mixture according to claim 1 , characterized in that for 25 pm glass fibers, the mixture preferably comprises 20% powdered glass fiber and preferably 80% phenol-formaldehyde adhesive to achieve optimal seating torque.4) The mixture according to claim 1 , characterized in that the powdered glass fiber and adhesive mixture is distributed homogeneously between the layers of a 7-layer plywood panel.

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