阅读说明：本技术 一种泡沫材料及其制备方法和应用 (Foam material and preparation method and application thereof ) 是由 廖望 周琦 严礼萍 李丽 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种泡沫材料及其制备方法和应用,该材料由天然多糖、富氮高分子、交联剂和增韧剂组成,该泡沫材料的制备方法包括称量、混合、固化和除冰。本发明提供的泡沫材料密度为5～25 kg/m<Sup>3</Sup>,比模量10～200 MPa·cm<Sup>3</Sup>/g,孔隙率85～98%,比表面积60～150 m<Sup>2</Sup>/g,可用于制作水果、蔬菜果实和鲜花的泡沫网兜。该材料除了具有减震作用外,还对花、果具有抑菌保鲜作用,典型地,可将水蜜桃的货架期从4～5天增加至约15天,因此,本发明材料显著的减少了果实的腐烂,延长了货架期,且食用安全性高；本发明公开的泡沫材料的制备方法操作简单、制备方便、节能环保、适用于工业化大规模生产。(The invention discloses a foam material and a preparation method and application thereof, wherein the material is composed of natural polysaccharide, nitrogen-rich polymer, a cross-linking agent and a toughening agent, and the preparation method of the foam material comprises weighing, mixing, curing and deicing. The density of the foam material provided by the invention is 5-25 kg/m 3 Specific modulus of 10-200 MPa cm 3 The specific surface area is 60-150 m, the porosity is 85-98% 2 The foam net bag can be used for preparing foam net bags for fruits, vegetables, fruits and flowers. The material has a shock absorption effect, also has a bacteriostatic and fresh-keeping effect on flowers and fruits, and can increase the shelf life of honey peaches from 4-5 days to about 15 days typically, so that the material obviously reduces the rotting of fruits, prolongs the shelf life and has high edible safety; the preparation method of the foam material disclosed by the invention is simple to operate, convenient to prepare, energy-saving and environment-friendly, and is suitable for industrial large-scale production.)

1. The foam material is characterized by comprising the following raw materials in parts by weight:

natural polysaccharides: 0.1 to 10; nitrogen-rich polymer: 0.1 to 10;

a crosslinking agent: 0.005 to 2; a toughening agent: 0 to 2.

2. The foam material of claim 1, which comprises the following raw materials in parts by weight:

natural polysaccharides: 0.5 to 5; nitrogen-rich polymer: 0.5 to 5;

a crosslinking agent: 0.001 to 1; a toughening agent: 0 to 1.

3. The foam material of claim 1, which comprises the following raw materials in parts by weight:

natural polysaccharides: 3; nitrogen-rich polymer: 2;

a crosslinking agent: 0.5; a toughening agent: 0.07.

4. A foam material according to claim 1, 2 or 3, wherein the natural polysaccharide is one or more of cellulose, starch, alginate, dextrin, cyclodextrin, sorbitol, mannitol.

5. A foam material according to claim 1, 2 or 3, wherein the nitrogen-rich polymer is one or more of chitosan, casein, gelatin, polyethyleneimine.

6. A foam material according to claim 1, 2 or 3 wherein the cross-linking agent is one or more of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, borax, boric acid, phosphoric acid, phytic acid, glutaraldehyde.

7. A foam material according to claim 1, 2 or 3, wherein the toughening agent is a phthalate or a polyamide.

8. A process for the preparation of a foam according to claim 1, 2 or 3, characterized in that it comprises the following steps:

s1, weighing: weighing the raw materials according to the formula proportion for later use;

s2, mixing: dissolving the weighed natural polysaccharide, the nitrogen-rich polymer and the toughening agent in water, uniformly mixing, adding the crosslinking agent, and uniformly mixing again;

s3, curing: solidifying the mixed solution at a temperature of-196 to-20 ℃ in a freezing way;

s4, deicing: and drying the solidified solid for deicing to prepare the foam material.

9. The method of claim 8, wherein the drying step S4 is one or more of freeze drying, vacuum drying and atmospheric drying.

10. Use of a foam according to any one of claims 1 to 3 in the field of freshness-retaining net bags for fruits, vegetables, fruits or flowers.

Technical Field

The invention belongs to the technical field of organic material preparation, and particularly relates to a foam material and a preparation method and application thereof.

Background

The preservation of fruits is a worldwide problem. The problem of poor storage results in a substantial portion of the fruit being of reduced commercial value, while also limiting its range of supply. Typical cases such as juicy peaches belong to climacteric fruits, have thin and juicy peels, high water content and good mouthfeel, and are widely loved by consumers. However, the fruits mature in hot summer, the temperature is high in the harvesting period, the fruits have high field heat, the respiration effect is vigorous, the fruits can be quickly softened after being picked, the phenomena of mechanical property damage or rot after being infected by germs are common, and the shelf life at normal temperature is only 3-5 days.

At present, the main fresh-keeping methods of fruits mainly comprise:

(1) a drug treatment method, namely, preservative suitable for fruit postharvest treatment, such as preservative solution prepared from captafol, potassium permanganate, chlormequat chloride, benzylpurine and other drugs, and the fruit is soaked or fumigated to inhibit diseases and physiological activities of microorganisms. In the storage process, the rot caused by microorganisms is reduced, the physiological and biochemical change speed after the picking is reduced, and the storage life is slightly prolonged. However, consumer repugnance to the drug-treated fruit is common due to potential health effects.

(2) Low temperature storage method. The fruit fresh-keeping method does not enter a practical application stage because the fruit fresh-keeping method does not enter a circulating cold chain in China.

(3) Air-conditioned cold storage method. The method has high cost for keeping the fruits fresh, and the total yield of the fruits stored by the method is less than 1 percent.

(4) And (4) a film coating preservation method. The method has the advantages of real-time fruit treatment alone and limited preservation effect.

(5) And (4) a pressure regulation method. The method is characterized in that a storage environment with a certain vacuum degree and low oxygen concentration is obtained by reducing the gas pressure in a closed environment, the method is also favorable for outward diffusion of harmful gases, and the method is restricted due to large equipment investment in actual production.

(6) Ethylene inhibitor treatment. Such as 1-methylcyclopropene treatment, which irreversibly competes with ethylene receptors, effectively inhibits the action of ethylene, delays a series of physiological evolutionary processes induced by ethylene, and effectively delays the after-ripening of fruits. Although the storage life of the fruit can be prolonged, the microbial diseases and physiological diseases of the fruit are easily increased.

As is well known, the method of using the foam net bag to pack fruits and reducing or eliminating mechanical damage of the fruits during transportation and sale in a shock absorption manner to effectively improve the shelf life of the fruits is a commonly used method at present. Currently, the material of the foam net bag is mainly soft polyurethane foam. Chinese patent CN104831585A discloses a preservative paper specially used for honey peaches. The fresh-keeping effect of the honey peaches is realized by dissolving lysozyme, VC derivatives, chitosan, galangal and auxiliary components in water and then uniformly coating the solution on common wrapping paper. Chinese patent CN105918429A discloses a fresh-keeping treatment method for Fenghuang honey peach, which comprises preparing starch, glycerol, polyvinyl alcohol, monoglyceride, sodium alginate, lysozyme and ascorbic acid into solution, spraying the solution on the honey peach primarily sterilized by ultraviolet, air drying, and storing. However, the above treatment method still cannot avoid damage caused by physical collision between boxed fruits, vegetables, fruits or flowers, and greatly shortens shelf life.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a foam material with the capabilities of shock absorption and bacteriostasis;

the second object of the present invention is to provide a process for the preparation of such foams;

a third object of the invention is to provide the use of such a foam.

The purpose of the invention is realized by the following technical scheme: a foam material comprises the following raw materials in parts by weight:

natural polysaccharides: 0.1 to 10; nitrogen-rich polymer: 0.1 to 10;

a crosslinking agent: 0.005 to 2; a toughening agent: 0 to 2.

Further, the feed additive comprises the following raw materials in parts by weight:

natural polysaccharides: 0.5 to 5; nitrogen-rich polymer: 0.5 to 5;

a crosslinking agent: 0.001 to 1; a toughening agent: 0 to 1.

As a preferred scheme, the fertilizer comprises the following raw materials in parts by weight:

natural polysaccharides: 3; nitrogen-rich polymer: 2;

a crosslinking agent: 0.5; a toughening agent: 0.07.

further, the natural polysaccharide is one or more of cellulose, starch, alginate, dextrin, cyclodextrin, sorbitol and mannitol.

Further, the nitrogen-rich polymer is one or more of chitosan, casein, gelatin and polyethyleneimine.

Further, the cross-linking agent is one or more of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, borax, boric acid, phosphoric acid, phytic acid and glutaraldehyde.

Further, the toughening agent is phthalate or polyamide.

A method of preparing a foam material comprising the steps of:

s1, weighing: weighing the raw materials according to the formula proportion for later use;

s2, mixing: dissolving the weighed natural polysaccharide, the nitrogen-rich polymer and the toughening agent in water, uniformly mixing, adding the crosslinking agent, and uniformly mixing again;

s3, curing: solidifying the mixed solution at a temperature of-196 to-20 ℃ in a freezing way;

s4, deicing: and drying the solidified solid for deicing to prepare the foam material.

Further, the drying in step S4 is one or more of freeze drying, vacuum drying or atmospheric drying.

The foam material is applied to the field of the fresh-keeping net bags for fruits, vegetables, fruits or flowers.

The invention has the following advantages: the invention provides a novel foam material, and the density of the foam material is 5-25 kg/m³Specific modulus of 10-200 MPa cm³The specific surface area is 60-150 m, the porosity is 85-98%²The foam net bag can be used for preparing foam net bags for fruits, vegetables, fruits and flowers. The material has a shock absorption effect, also has a bacteriostatic and fresh-keeping effect on flowers and fruits, and can increase the shelf life of honey peaches from 4-5 days to about 15 days typically, so that the material obviously reduces the rotting of fruits, prolongs the shelf life and has high edible safety; the preparation method of the foam material disclosed by the invention is simple to operate, convenient to prepare, energy-saving and environment-friendly, and is suitable for industrial large-scale production.

Detailed Description

The invention is further described below with reference to examples, without limiting the scope of the invention to the following: