A modified soybean protein adhesive and its preparation method

Abstract

The invention provides a modified soy protein adhesive and a preparation method thereof. A preparation process is as below: (1) adding the defatted soybean flour, water, sodium dodecyl benzene sulfonate and alkali into a reactor, stirring for 5 min, adding ethylene glycol and silicone oil, rising the temperature to 90 DEG C, insulating and stirring for 3 h, cooling, and discharging the materials, so as to obtain a soybean protein pre-hydrolyzed solution; and (2) before usage, adding a homemade or purchased melamine-formaldehyde resin into the soybean protein pre-hydrolyzed solution as a crosslinking agent for the soybean protein, and uniformly mixing at room temperature. The modified soybean protein adhesive by the invention has simple technology, simple and flexible operation and moderate cost. The adhesive has excellent water resistant property, and a prepared poplar glued board test piece has bond strength no less than 0.7 MPa after impregnation in water at (63+ / -3) DEG C for 3 h, shows no glue phenomenon, and has reached the requirements of national standard type II GB / T9846.3-2004 for glued boards.

Description

technical field

[0001] The invention relates to a modified soybean protein adhesive and a preparation method thereof. The soybean protein adhesive is mainly used in the production of wood-based panels and furniture, and belongs to the technical field of wood adhesives. Background technique

[0002] Wood adhesive is an important raw material for wood-based panel production, and the performance of the adhesive has a direct impact on the performance of the final wood-based panel product and the use environment. At present, the adhesives used in the wood-based panel industry are mostly synthetic resin adhesives, among which "trialdehyde" glue (ie urea-formaldehyde resin, phenolic resin, melamine-formaldehyde resin) is the most widely used. The common feature of "trialdehyde" glue is the use of formaldehyde raw materials. However, due to the toxicity of formaldehyde, how to reduce the amount of formaldehyde released in aldehyde resins has always been a key technical problem that ...

Examples

Embodiment 1

[0021] (1) Add 80 parts of defatted soy flour, 148 parts of water, 0.8 parts of sodium dodecylbenzenesulfonate, 6.4 parts of NaOH into the reaction kettle, start the mechanical stirring bar, and after stirring for 5 minutes, add 1.6 parts of ethylene glycol, 10 Drop silicone oil, raise the temperature to 90°C, and keep the reaction time for 3 hours, then discharge after cooling to obtain soybean protein prelyzed liquid.

[0022] (2) Add 150 parts of 37% formaldehyde solution to the reaction kettle, and adjust the pH to 9.0 with an appropriate amount of 30% NaOH solution. Add 80 parts of melamine, raise the temperature to 85°C, keep the temperature for reaction for 2 hours, then immediately cool to 40°C, adjust the pH to 9.0 with NaOH solution and discharge to obtain melamine-formaldehyde resin.

[0023] (3) Add 10.7 parts of melamine-formaldehyde resin to the soybean protein prelyzed solution, mix and stir evenly.

Embodiment 2

[0025] (1) Add 80 parts of defatted soy flour, 187 parts of water, 4.8 parts of NaOH and 1.9 parts of CaO into the reaction kettle, start the mechanical stirring bar, stir for 5 minutes, add 1.6 parts of ethylene glycol, 10 drops of silicone oil, and heat up to 90°C , and after keeping the reaction time for 3 hours, discharge after cooling to obtain soybean protein prelyzed solution.

[0026] (2) Add 150 parts of 37% formaldehyde solution to the reaction kettle, and adjust the pH to 9.2 with an appropriate amount of 30% NaOH solution. Add 95 parts of melamine, raise the temperature to 85°C, keep the temperature for reaction for 3 hours, then immediately cool to 40°C, adjust the pH to 9.0 with NaOH solution and discharge to obtain melamine-formaldehyde resin.

[0027] (3) Add 14.2 parts of melamine-formaldehyde resin to the soybean protein prelyzed solution, mix and stir evenly.

Embodiment 3

[0029] (1) Add 80 parts of defatted soy flour, 220 parts of water, 1.6 parts of sodium dodecylbenzenesulfonate, and 8 parts of KOH into the reactor, start the mechanical stirring bar, and after stirring for 5 minutes, add 3.2 parts of ethylene glycol, 10 Drop silicone oil, raise the temperature to 90°C, and keep the reaction time for 3 hours, then discharge after cooling to obtain soybean protein prelyzed solution.

[0030] (2) Add 17.8 parts of melamine-formaldehyde resin to the soybean protein adhesive, mix and stir evenly. Among them, the melamine-formaldehyde resin is commercially available as a colorless transparent liquid with a solid content of 45%, a viscosity (20°C) of 70 mPa·s, a pH value of 9.2, and a molar ratio of melamine to formaldehyde M / F of 1:2.67.

technical field

[0001] The invention relates to a modified soybean protein adhesive and a preparation method thereof. The soybean protein adhesive is mainly used in the production of wood-based panels and furniture, and belongs to the technical field of wood adhesives. Background technique

[0002] Wood adhesive is an important raw material for wood-based panel production, and the performance of the adhesive has a direct impact on the performance of the final wood-based panel product and the use environment. At present, the adhesives used in the wood-based panel industry are mostly synthetic resin adhesives, among which "trialdehyde" glue (ie urea-formaldehyde resin, phenolic resin, melamine-formaldehyde resin) is the most widely used. The common feature of "trialdehyde" glue is the use of formaldehyde raw materials. However, due to the toxicity of formaldehyde, how to reduce the amount of formaldehyde released in aldehyde resins has always been a key technical problem that ...

Examples

Embodiment 1

[0021] (1) Add 80 parts of defatted soy flour, 148 parts of water, 0.8 parts of sodium dodecylbenzenesulfonate, 6.4 parts of NaOH into the reaction kettle, start the mechanical stirring bar, and after stirring for 5 minutes, add 1.6 parts of ethylene glycol, 10 Drop silicone oil, raise the temperature to 90°C, and keep the reaction time for 3 hours, then discharge after cooling to obtain soybean protein prelyzed liquid.

[0022] (2) Add 150 parts of 37% formaldehyde solution to the reaction kettle, and adjust the pH to 9.0 with an appropriate amount of 30% NaOH solution. Add 80 parts of melamine, raise the temperature to 85°C, keep the temperature for reaction for 2 hours, then immediately cool to 40°C, adjust the pH to 9.0 with NaOH solution and discharge to obtain melamine-formaldehyde resin.

[0023] (3) Add 10.7 parts of melamine-formaldehyde resin to the soybean protein prelyzed solution, mix and stir evenly.

Embodiment 2

[0025] (1) Add 80 parts of defatted soy flour, 187 parts of water, 4.8 parts of NaOH and 1.9 parts of CaO into the reaction kettle, start the mechanical stirring bar, stir for 5 minutes, add 1.6 parts of ethylene glycol, 10 drops of silicone oil, and heat up to 90°C , and after keeping the reaction time for 3 hours, discharge after cooling to obtain soybean protein prelyzed solution.

[0026] (2) Add 150 parts of 37% formaldehyde solution to the reaction kettle, and adjust the pH to 9.2 with an appropriate amount of 30% NaOH solution. Add 95 parts of melamine, raise the temperature to 85°C, keep the temperature for reaction for 3 hours, then immediately cool to 40°C, adjust the pH to 9.0 with NaOH solution and discharge to obtain melamine-formaldehyde resin.

[0027] (3) Add 14.2 parts of melamine-formaldehyde resin to the soybean protein prelyzed solution, mix and stir evenly.

Embodiment 3

[0029] (1) Add 80 parts of defatted soy flour, 220 parts of water, 1.6 parts of sodium dodecylbenzenesulfonate, and 8 parts of KOH into the reactor, start the mechanical stirring bar, and after stirring for 5 minutes, add 3.2 parts of ethylene glycol, 10 Drop silicone oil, raise the temperature to 90°C, and keep the reaction time for 3 hours, then discharge after cooling to obtain soybean protein prelyzed solution.

[0030] (2) Add 17.8 parts of melamine-formaldehyde resin to the soybean protein adhesive, mix and stir evenly. Among them, the melamine-formaldehyde resin is commercially available as a colorless transparent liquid with a solid content of 45%, a viscosity (20°C) of 70 mPa·s, a pH value of 9.2, and a molar ratio of melamine to formaldehyde M / F of 1:2.67.