CN111231046B

CN111231046B - Nut compacting plate based on high frequency technology and manufacturing method thereof

Info

Publication number: CN111231046B
Application number: CN202010100400.5A
Authority: CN
Inventors: 王凯
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-02-18
Filing date: 2020-02-18
Publication date: 2021-11-02
Anticipated expiration: 2040-02-18
Also published as: JP7033334B2; JP2021130298A; CN111231046A

Abstract

The invention relates to a method for manufacturing a nut compacting plate based on a high frequency technology, which comprises the following steps: a pretreatment step: taking a PVB intermediate film for later use; mixing the nut skin and PVB resin particles, wherein the ratio of the weight of the PVB resin particles plus the PVB intermediate film to the weight of the walnut skin crushed materials is 0.8-1.5: 10; a prepressing body preparation step: adding all the PVB intermediate film and the mixture into a mould according to a mode of adding a layer of PVB intermediate film and a layer of mixture to obtain a prepressing body; a heating and pressurizing treatment step: compressing the pre-compact, wherein the compression conditions are as follows: high frequency of 3-10MHz, hot pressing temperature of 80-160 deg.C, hot pressing time of 4-600 s, and pressure of 1-10 MPa. The invention has the advantages of providing a plurality of compaction plates which have excellent processing performance and moisture resistance and retain the inherent fragrance of nuts and a preparation method thereof.

Description

Nut compacting plate based on high frequency technology and manufacturing method thereof

Technical Field

The invention belongs to the technical field of lamination, and particularly relates to a nut compacting plate based on a high-frequency technology and a manufacturing method thereof.

Background

The nut skins are hard and a large amount of nut skins are produced as waste due to the nutritional abundance of nuts available for consumption each year. There have been some attempts to make slabs from waste nut skins, but evaluation of slabs generally involves several criteria, such as processability, moisture resistance, and even odor. Raising or improving some of the attributes of the panel reduces or improves some of the other attributes of the panel, and thus there is currently no report of making nut laminates that retain the hard characteristics of the nut shell and the inherent flavor of the nuts, nor any nut laminate that has yet been moisture resistant. For example, the Chinese patent CN 106426427A uses plant fiber containing walnut shell powder, needs to be added with a treating agent to keep 38 ℃ for dipping treatment for 3-6 hours, and is formed by hot pressing by a hot press, however, the method is not favorable for keeping the inherent fragrance of nut skins and the inherent hard characteristic of the nut skins, and simultaneously has lower moisture resistance. For another example, chinese patent CN 109703152 a discloses a moisture-proof layer of a moisture-proof and noise-proof board: is prepared from straw (85-90%), nut shell and moisture-proof urea-formaldehyde resin adhesive (10-15%) through mixing, pre-pressing and hot pressing. However, the free formaldehyde contained in urea-formaldehyde resins is toxic, and the moisture resistance is too low when the amount of urea-formaldehyde resin used is too small.

Disclosure of Invention

In order to solve the technical problem, the invention provides a method for manufacturing a nut compacting plate based on a high frequency technology, which comprises the following steps:

a pretreatment step: taking a PVB intermediate film for later use; mixing the nut skin and PVB resin particles, wherein the ratio of the weight of the PVB resin particles plus the PVB intermediate film to the weight of the walnut skin crushed materials is 0.8-1.5: 10;

a prepressing body preparation step: adding all the PVB intermediate film and the mixture into a mould according to a mode of adding a layer of PVB intermediate film and a layer of mixture to obtain a prepressing body;

a heating and pressurizing treatment step: compressing the pre-compact, wherein the compression conditions are as follows: high frequency of 3-10MHz, hot pressing temperature of 80-160 deg.C, hot pressing time of 4-600 s, and pressure of 1-10 MPa.

The PVB intermediate film is mainly prepared from PVB resin. The PVB resin is a high molecular compound obtained by reacting polyvinyl alcohol and butyraldehyde under the catalysis of strong acid. Commercially available PVB interlayers and PVB resins are within the purview of the present invention and the present invention is not limited in any way.

The nuts of the present invention include, but are not limited to, chestnuts, cashews, walnuts, melon seeds, almonds, pistachios, hazelnuts, and peanuts.

Further, the ratio of the weight of the PVB resin particles plus the PVB intermediate film to the weight of the nut peel is 0.9-1.0: 10.

The PVB resin particles are PVB resin fiber particles, and the PVB resin fiber particles are prepared by the steps of carrying out hot melting, mixing, extruding and cooling on PVB resin and lignin fibers in a weight ratio of 0.5: 0.1-0.5.

Further, the ratio of the PVB resin to the lignin fiber in parts by weight is 0.5: 0.2-0.3.

The grain size of the nut peel is 1-10 mm.

Furthermore, the grain size of the nut peel is 2-5 mm.

The water content of the nut peel is 5-15%.

Furthermore, the water content of the nut peel is 8-12%.

The preparation method of the invention also comprises a curing treatment step: the nut skin plate subjected to heating and pressurizing treatment is heated to the temperature of 180-220 ℃ by high frequency, and is subjected to heat preservation for 5-8min for curing treatment to obtain the cured nut skin plate.

The preparation method of the invention also comprises the cooling treatment step: the solidified surface of the nut skin plate is cooled at a speed of 5-15 ℃/min by using a water cooling technology until the temperature of the nut skin plate is 70-90 ℃, the water flow rate of the water cooling technology is 0.9-1.5m/s, and when the surface temperature of the nut skin plate is cooled to 85-90 ℃, air cooling is carried out, wherein the air speed is 9.2-9.7m/s, and the air temperature is 55-60 ℃.

The invention also provides a nut compacting plate based on high frequency technology, which is obtained by the preparation method.

The invention has the advantages of providing a plurality of compaction plates which have excellent processing performance and moisture resistance and retain the inherent fragrance of nuts and a preparation method thereof.

Drawings

FIG. 1 shows a high frequency walnut shell compacting plate according to an embodiment of the present invention.

Detailed Description

Example 1 high frequency nut compacting plate (walnut skin)

A pretreatment step: taking 10kg of walnut skin crushed aggregates with the particle size of 2-5mm, the average water content of the walnut skin crushed aggregates is 10.1%, taking 0.5kg of PVB resin particles with the particle size of 1-5mm (purchased from Shanghai Meibang plastics Co., Ltd., the same below), 0.5kg of PVB intermediate film with the thickness of 1.2mm (10 sheets, 50g of each sheet, purchased from Shanghai Meibang plastics Co., Ltd., the same below) and the resin-material ratio of 1:10, and mixing the walnut skin crushed aggregates and the PVB resin particles to obtain a mixture.

A prepressing body preparation step: selecting a pressing plate type high-frequency hot press, placing a mould (a softwood wood frame with the length of 55CM, the width of 35CM, the thickness of 17CM, no top and no bottom) on demoulding paper of a lower hot press plate, and adding all PVB intermediate films and mixtures into the mould in a mode of adding a layer of PVB intermediate film and a layer of mixtures into the mould to obtain a prepressing body;

a heating and pressurizing treatment step: compressing the pre-pressing body, wherein the high frequency is 4MHz, the hot pressing temperature is 140 ℃, the hot pressing time is 7 seconds, and the pressure is 5 Mpa.

Cutting and polishing: and (5) cutting edges and polishing the surface of the cooled walnut skin plate. Pressing for 5 times to obtain 3 pieces of high frequency walnut compact plates (density 0.6g/CM3) with length 50CM, width 30CM and thickness 5 CM.

Examples 2-7 high cycle nut compacting plates

Referring to example 1, Table 1 shows the "heat and pressure treatment" parameters and the batch conditions for preparation examples 2-7, the PVB interlayer was used in the same amount as in example 1.

Table 1: examples 2 to 7

Example 8

Prepared by the method of reference example 1 except as follows:

a pretreatment step: taking 10kg of walnut skin crushed materials with the particle size of 2-5mm, the average water content of the walnut skin crushed materials is 10.4%, taking 1kg of PVB resin particles with the particle size of 2.5mm, the resin-material ratio of the PVB resin particles is 1:10, adding the walnut skin crushed materials after the PVB resin particles are hot-melted, soaking the walnut skin crushed materials for 6 hours under stirring to obtain a soaking material, and cooling the soaking material.

A prepressing body preparation step: a pressing plate type high-frequency hot press is selected, a mould (a softwood wood frame with the length of 55CM, the width of 35CM, the thickness of 17CM, no top and no bottom) is placed on the demoulding paper of a lower hot pressing plate, and impregnating materials are added into the mould.

Examples 9 to 14

Referring to example 1, table 2 shows the "heat and pressure treatment" parameters and batch conditions for the preparation of examples 9-14, where example 13 uses only PVB interlayer film and walnut skin particles are not required to make a blend, and example 14 uses only PVB interlayer film and PVB resin particles to make a blend without laying PVB interlayer film.

Table 2: examples 9 to 14

Example 15

Prepared by the method of reference example 1, except that:

the PVB resin fiber particle preparation step is to melt 1kg of PVB resin, add loose 0.5kg of flocculent lignin fiber (Wuxi Lujian technology limited, the same below), keep the molten state, stir for 5-15min, mix, take out and slightly cool, keep the mixture in the semi-solid state, and obtain PVB resin fiber particles (cylindrical, the average diameter and height of the cylinder is 2.5 mm).

A pretreatment step: 10kg of walnut skin crushed materials with the particle size of 2-5mm are taken, the average water content is 10.6%, 0.5kg of PVB intermediate film with the thickness of 1.2mm is taken for standby, 0.75kg of PVB resin fiber particles are taken and mixed to prepare a mixture, and the resin-material ratio is 1: 10.

A prepressing body preparation step: selecting a pressing plate type high-frequency hot press, placing a mould (a softwood wood frame with the length of 55CM, the width of 35CM, the thickness of 17CM, no top and no bottom) on the demoulding paper of a lower hot press plate, and adding all PVB intermediate films and mixtures into the mould in a mode of adding a layer of PVB intermediate film and a layer of mixtures into the mould;

examples 16 to 25

Referring to example 15, Table 3 shows the "heat and pressure treatment" parameters and the feed conditions of preparation examples 16 to 25.

Table 3: examples 16 to 25

Example 26

Referring to example 15, further comprising a curing process step: heating the walnut skin plate subjected to heating and pressurizing treatment by high frequency till the temperature of the walnut skin plate is 180 ℃, preserving heat for 8min, carrying out curing treatment to obtain a cured walnut skin plate, and cooling.

Example 27

Referring to example 15, further comprising a cooling process step: cooling the surface of the solidified walnut skin plate at the speed of 5-15 ℃/min by using a water cooling technology until the temperature of the walnut skin plate is 70 ℃, and the water flow rate of the water cooling technology is 0.9 m/s; when the surface temperature of the walnut skin plate is cooled to 90 ℃, air cooling is carried out, the wind speed is 9.2m/s, and the wind temperature is 55 ℃.

Examples 28 to 31

Referring to examples 26 and 27, examples 28-31 were prepared, respectively, corresponding to conditions table 4.

Table 4: examples 28 to 31

The present invention will be further described with reference to test examples.

Test example 1 processability and odor test

The test method comprises the following steps: examples 1 to 7 were set as test examples 1 to 7, respectively, and examples 15 to 17 were set as test examples 8 to 10, respectively; examples 8-14 as comparative examples 1-7, processability and odor tests were conducted.

The processing performance test method comprises the following steps: after sawing, drilling, slotting, tenoning and sanding, observing the appearance of an operation part, wherein the appearance is divided into four grades of excellent, good, common and poor; the odor test method comprises the following steps: whether the nut odor was present was judged at 0 month, 1 month, 6 months, and 24 months, respectively, "brief" if there was a strong odor at 0 month and a weak odor at 1 month, "normal" if there was a strong odor at 1 month and a weak odor at 6 months, and "permanent" if there was a strong odor at 6 months and a weak odor at 24 months, see table 6.

TABLE 6 processability and odor test

And (3) test results: the test examples 1 to 4, 8 to 10 showed excellent processability and a long-lasting walnut flavor. Test examples 5-6 also exhibited excellent processability and a long-lasting almond flavor and hazelnut flavor. The sample of example 7 also had a long-lasting peanut flavor, and the processability was also substantially satisfactory. Comparative example 1 shows that the crushed walnut skin treated by the impregnation process has only a short walnut taste. The resin-to-material ratios of comparative examples 2 and 3 were 1.7:10 and 1.6:10, respectively, indicating that increasing the amount of resin used can maintain better processability, but greatly affects the odor release. The resin-to-material ratios of comparative example 4 and comparative example 5 were 0.6:10 and 0.7:10, respectively, indicating that reducing the amount of resin used can maintain the odor release, but the processability is greatly reduced. Comparative example 6, using only PVB interlayer, shows that as the number of layers of the film increases, the processability remains superior, but this adds complexity to the process for production and the odor remains for a typical time. Comparative example 7 uses only PVB resin pellets and eliminates the film-laying step during the process, however, drilling, grooving, tenoning performance is reduced and odor is maintained for a typical period of time.

Test example 2 Water absorption thickness expansion Rate

The test method comprises the following steps: examples 1 to 3 were used as test examples 1 to 3, respectively, and examples 15 to 17 were used as test examples 4 to 6, respectively; the water absorption thickness expansion ratio test was conducted for examples 13 to 14 as comparative examples 1 to 2, respectively, and for examples 9 to 10 as comparative examples 3 to 4, respectively.

The water absorption thickness expansion rate test method refers to 6.3.4 water absorption thickness expansion rate test of GB/T18102-2007.

Test piece: taking a comparison test article, and cutting 1 time along the length direction and the width direction respectively to obtain 2 test pieces, wherein the size of each test piece is 150mm in length and 50mm in width.

The instrument comprises the following steps: constant temperature water tank (Nanjing Kenkun electronic technology Co., Ltd.), temperature regulation range: (20 +/-1) DEG C. Micrometer with precision of 0.01 mm.

The method comprises the following steps: soaking the test piece in distilled water tank at 20 + -1 deg.C for 24 hr + -15min, wherein the test piece is placed in the distilled water tank perpendicular to the horizontal plane, the lower surface of the test piece is spaced from the bottom of the distilled water tank, and a gap is formed between the test pieces for free expansion. After the immersion, the test piece was taken out, the surface water was wiped off, and the thickness h2 was measured at the original measurement point. The measurement must be completed within 30 min.

The water absorption thickness expansion rate of the test specimen is calculated as the ratio of the thickness increase of the specimen after water absorption to the thickness before water absorption, and the water absorption thickness expansion rate of each specimen is expressed in percentage and is calculated according to the formula 1 to be accurate to 0.1 percent.

D ═ h2-h1)/h1 ═ 100 formula 1

In the formula: d-water absorption thickness expansion rate,%; h 1-thickness of test piece before immersion in water, in units of millimeters (mm); h 2-thickness of test piece after immersion in water, in millimeters (mm). The arithmetic mean of the water absorption thickness swelling ratios of the test pieces at 6 measurement points was calculated to 0.1%, and the results are shown in table 7.

TABLE 7 Water absorption thickness expansion ratio

And (3) test results: the water absorption thickness expansion rate in 48 hours of the test examples 1-6 is lower than that of the comparative examples 1 and 2, which shows that the PVB resin particles and the PVB intermediate film are mixed for use and have better synergistic effect with the high-frequency hot-pressing condition. Comparative examples 3 and 4 show that increasing the resin-to-material ratio failed to further reduce the water absorption thickness swell ratio, and that the water absorption thickness swell ratios of 24h and 48h were also increased.

Test example 3 dimensional stability

The test method comprises the following steps: examples 15 to 17 were used as test examples 1 to 3, respectively, and examples 26 to 31 were used as test examples 4 to 9, respectively; examples 22-25 were conducted as comparative examples 1-4, respectively, and dimensional stability tests were conducted.

The test method refers to 6.3.10 dimensional stability test of GB/T18102-2007.

Instruments and tools: the temperature and humidity regulating box (Shanghai Suyun testing apparatus Co., Ltd.) can control the temperature to be 23 +/-2 ℃ and the relative humidity to be 30% +/-3% and 90% +/-3%. And a vernier caliper with the measuring range of 250mm and the precision of 0.02 mm.

Test piece: length 180mm 20mm, taking one block, 3 blocks and 6 blocks respectively along the length direction and the width direction,

the test steps are as follows: a center line parallel to the length direction was drawn on each test piece.

All the test pieces are put into a temperature and humidity regulating box with the temperature of 23 +/-2 ℃ and the relative humidity of 30 +/-3 percent to be processed to be balanced, and the length of the original central line is measured to be accurate to 0.02 mm.

And then all the test pieces are put into a temperature and humidity regulating box with the temperature of 23 +/-2 ℃ and the relative humidity of 90 +/-3 percent to be processed to be balanced, and the length of the original central line is measured to be accurate to 0.02 mm.

Note: equilibrium is considered when the difference between the two measurements at 24h intervals does not exceed 0.05 mm.

And calculating and representing the result:

the dimensional change of each test piece was calculated according to equation (2) to the nearest 0.02 mm.

L2-L1 formula 2

In the formula: Δ L-dimensional change of the test piece in millimeters (mm); l2-length of test piece in millimeters (mm) after equilibration at a relative humidity of 90%; l1-length of test piece after equilibration at a relative humidity of 30%, in millimeters (mm); the dimensional change of the measured panel is expressed as an arithmetic mean of the dimensional changes of six test pieces to the nearest 0.02 mm.

Table 8 shows the dimensional stability under different particle sizes and water contents, and table 9 shows the dimensional stability under curing and cooling conditions.

TABLE 8 dimensional stability at different particle sizes and Water contents

And (3) test results: as can be seen from table 8, comparative example 1 and comparative example 2 are the moisture contents of the walnut shells of 4.2% and 16.3%, respectively, and the results show that too low moisture content and too high moisture content affect dimensional stability; comparative examples 3 and 4 are walnut skin particle sizes of 0.1 to 0.9mm and 11.22 to 15.3mm, respectively, and it was shown that too low particle size and too high particle size also affect dimensional stability. The results of test examples 1-3 demonstrate better dimensional stability.

TABLE 9 dimensional stability under curing and temperature reduction treatment conditions

And (3) test results: as can be seen from table 9, the samples of test examples 4 to 6, which are subjected to the increased curing step, and the samples of test examples 7 to 9, which are subjected to the increased cooling treatment step, exhibited better dimensional stability, which is not much different from that of test examples 1 to 3, but was significantly better than that of test examples 10 to 12, indicating that the PVB resin fiber particles had more excellent performance in enhancing dimensional stability.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims

1. A method for making a nut compacting plate based on high frequency technology, comprising:

a pretreatment step: taking a PVB intermediate film for later use; mixing nut skins and PVB resin particles, wherein the ratio of the weight of the PVB resin particles plus the PVB intermediate film to the weight of the nut skin crushed materials is 0.8-1.5: 10; the PVB resin particles are prepared by the steps of carrying out hot melting, mixing, extruding and cooling on PVB resin and lignin fiber with the weight ratio of 0.1-0.5: 0.1-0.5;

2. The process of claim 1 wherein the ratio of the weight of said PVB resin particles plus said PVB interlayer to the weight of said nut skins is from 0.9 to 1.0: 10.

3. The method of claim 1 wherein the ratio of parts by weight of said PVB resin to said lignin fiber is from 0.5:0.2 to 0.3.

4. The method of claim 1, wherein said nut skins have a particle size of 1mm to 10 mm.

5. The method of claim 4, wherein said nut skins have a particle size of 2mm to 5 mm.

6. The method of claim 1, wherein said nut skins have a moisture content of 5% to 15%.

7. The method of claim 6, wherein said nut skins have a moisture content of between about 9% and about 12%.

8. The method of claim 1, further comprising one or more of the following steps:

a curing treatment step: heating the nut skin plate subjected to heating and pressurizing treatment to the temperature of 180-220 ℃ by using high frequency, preserving the heat for 5-8min, and performing curing treatment to obtain a cured nut skin plate;

cooling treatment: cooling the solidified surface of the nut skin plate at a speed of 5-15 ℃/min by using a water cooling technology until the temperature of the nut skin plate is 70-90 ℃, wherein the water flow rate of the water cooling technology is 0.9-1.5m/s, and when the surface temperature of the nut skin plate is cooled to 85-90 ℃, carrying out air cooling at a wind speed of 9.2-9.7m/s and a wind temperature of 55-60 ℃.

9. The high frequency technology based nut compaction plate of any one of claims 1 to 8.