CN105061991A - Heterogeneous nucleation principle foaming-based melamine foam and preparation method thereof - Google Patents

Abstract

The invention discloses a heterogeneous nucleation principle foaming-based melamine foam. The foam comprises, by weight, 100 parts of expandable melamine resin, 5-10 parts of a surfactant, 5-20 parts of a solidifying agent and 3-10 parts of a nucleating agent. The heterogeneous nucleation principle foaming-based melamine foam is prepared through the following steps: mixing above raw materials in a certain way, pouring the obtained mixture into a die, carrying out microwave foaming, and carrying out oven solidification. A preparation method also disclosed in the invention reduces or avoids a foaming agent, greatly reduces pollution caused by dissipation of the foaming agent, and also has the advantages of simple process, low production cost, and convenient popularization and application.

Description

A kind of melamine foamed plastic based on the foaming of heterogeneous nucleation principle and preparation method thereof

Technical field

The present invention relates to foam material, especially relate to a kind of based on heterogeneous nucleation principle, making foam of resin expanded gained and preparation method thereof by adding micron order solid particulate.

Background technology

Melamine foamed plastic is a kind of fire protection flame retarding foam materials emerging in recent years, its percentage of open area can reach more than 90%, and have that machine-shaping is convenient, chemical stability is good, cheap, difficult combustion, heat-resisting, burning time charring rate high rate of being fuming low, toxicity is little and without excellent specific properties such as molten drop thing, sound absorbing are strong.Through studying for many years both at home and abroad, the application of melamine foamed plastic in building, aerospace and car body obtains the accreditation in market gradually.

But the intensity of melamine foamed plastic is lower, foam brittleness is large, poor mechanical property, in addition, in the production process of common melamine foamed plastic, generally need add alkanes whipping agent, due to the high opening rate of trimeric cyanamide, this type of whipping agent can not remain in foam when gasifying foaming and directly spill in atmospheric environment, to the environment of surrounding, aggravation Greenhouse effect; Conventional alkanes whipping agent is inflammable and explosive, easily becomes disaster hidden-trouble in process of production.Therefore, the usage quantity reducing whipping agent in process of production economically or security standpoint see and be all highly profitable.

Summary of the invention

For the problems referred to above that prior art exists, the application provides a kind of melamine foamed plastic based on the foaming of heterogeneous nucleation principle and preparation method thereof.Product compressive strength of the present invention and Young's modulus are obviously strengthened, and thermal stability obtains lifting simultaneously; The present invention can reduce or not use whipping agent, significantly decreases the pollution that whipping agent loss produces, and preparation method's technique is simple, and low production cost is easy to utilize.

Technical scheme of the present invention is as follows:

Based on a melamine foamed plastic for heterogeneous nucleation principle foaming, the parts by weight of contained raw material and each raw material are:

The preparation method of described expandability melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 45%-60%;

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, add urotropine or 10% aqueous sodium hydroxide solution, adjust ph is to 8-8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:2.8-3.2;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction 1-2h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.

The preparation method of described melamine foamed plastic comprises the steps:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 5-10 part tensio-active agent, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 1200r/min, in the mixture of step (1) gained, add 3-10 part nucleator, continues to stir 3-5min;

(3) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (2) gained, add 5-20 part solidifying agent, continues to stir 3-10min;

(4) by mixture obtained for step (3), pour in the mould of preheating, rapid sealed mold, through microwave foaming 1-3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, namely demoulding feeding obtains the described melamine foamed plastic based on the foaming of heterogeneous nucleation principle.

In the process for preparation of described step (1) middle and high concentration formaldehyde solution, employing heats up and adds the method promotion paraformaldehyde powder dissolution of urotropine.

The solid content of described expandability melamine resin is 60-70%, and viscosity is 2000-7000mPas.

Described tensio-active agent is one or more in silicone oil, polyoxyethylene glycol, Span-80, tween-80, Viscotrol C polyvinyl ether, polyoxyethylene block copolymer.

Described nucleator is one or more in calcium carbonate, silicon-dioxide, titanium dioxide, hollow glass microbead; The particle diameter of described nucleator is 8 ~ 48 μm.

Described solidifying agent is organic acid or organic acid salt compounds.

Described solidifying agent is one or more in dilute hydrochloric acid, dilute sulphuric acid, oxalic acid, sulfocarbolic acid, ammonium chloride, tosic acid.

Described microwave foaming power is 300-800W.

The technique effect that the present invention is useful is:

1, the present invention is based on the foaming of heterogeneous nucleation principle, by adding micron order solid particulate, uniform foam cell degree is improved, aperture reduces, foam monolith compressive strength, Young's modulus, thermostability all increase, significantly decrease the usage quantity of whipping agent simultaneously, make that melamine foamed plastic becomes high-strength, green, the novel flame-retardant foam of environmental protection.

2, after the present invention adds micron order nucleator in resin system, due to the existence of solid-liquid two-phase interface, the free energy overcome needed for resin is changed into:

$\mathrm{\Δ}G=\frac{16{\mathrm{\π\ρ}}_{gm}^3}{3{\mathrm{\ΔP}}^2}S(\mathrm{\β},\mathrm{\θ})$

In formula, △ P is bubble inside and outside differential pressure; ρ _gmfor liquid-vapo(u)r interface tension force

$S(\mathrm{\β},\mathrm{\θ})=\frac{1}{2}-\frac{3}{4}cos\mathrm{\α}+\frac{1}{4}{\cos }^3\mathrm{\α}+\frac{1}{4}{\sin }^3\mathrm{\α}\·cos\mathrm{\β}/\sin \mathrm{\β}$

$\mathrm{\α}=\frac{\mathrm{\π}}{2}+\mathrm{\β}-\mathrm{\θ};$ 0＜α＜π；0＜β＜π

Known 0<S (β, θ) <1 is calculated by mathematics

So the free energy overcome needed for resin expanded at solid-liquid two-phase interface place reduces, resin surface at this place is long-pending more easily to be expanded, thus make resin without the need to by foaming agent foam or only need a small amount of whipping agent just can bubble successfully, larger solid particulate place more easily forms pore, uses micron order nucleator more scientific and reasonable.

3, the micron order solid particulate that the present invention adds not only as nucleator, can also can be used as the wild phase of melamine foamed plastic, improves mechanics and the thermal property of foam.

Accompanying drawing explanation

Fig. 1 is the scanning electron microscope (SEM) photograph of the embodiment of the present invention 1 gained froth product;

Fig. 2 is the scanning electron microscope (SEM) photograph of the embodiment of the present invention 2 gained froth product;

Fig. 3 is the scanning electron microscope (SEM) photograph of the embodiment of the present invention 3 gained froth product;

Fig. 4 is the scanning electron microscope (SEM) photograph of the embodiment of the present invention 4 gained froth product.

Embodiment

Below in conjunction with drawings and Examples, the present invention is specifically described.

Embodiment 1

Not containing the melamine foamed plastic of nucleator, concrete preparation method is as follows:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 5 parts of tween-80, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (1) gained, add 6 parts of oxalic acid and 3 parts of ammonium chlorides, continues to stir 5min;

(3) by mixture obtained for step (2), pour in the mould of preheating, rapid sealed mold, through microwave foaming (power is 800W) 3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, the melamine foamed plastic not containing nucleator described in namely demoulding feeding obtains.The scanning electron microscope (SEM) photograph of gained froth product as shown in Figure 1.

As seen from Figure 1, when not adding nucleator, foam structure morphology is more uneven, bubble wall poor morphology, foam structure irregularity, and the bubble wall thickness plastisied dispersion between each hole is higher, easily occurs stress concentration phenomenon when being subject to external force, easily broken; Through not measuring its abscess spacing from 0.07mm to 0.29mm not etc., the abscess spacing of 60% is distributed between 0.1-0.2mm, and at 0.1-0.47mm not etc., mean cell diameter is 0.28mm to its cell size, dispersion degree is comparatively large, and the highest only have the cell diameter of 35% to be distributed between 0.2-0.3mm; This illustrates when not adding nucleator, and the foaming effect of resin self is very uneven, thus easily forms uneven foam structure, have impact on it respectively to performance.

The preparation method of described expandability melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 50%; 80 DEG C of solubilisings are warming up to after adding 3% urotropine.

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, 10% aqueous sodium hydroxide solution is added, adjust ph to 8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:3;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction about 2h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.The solid content of above-mentioned expandability melamine resin is 62%, and viscosity is 4000mPas.

Embodiment 2

Based on a melamine foamed plastic for heterogeneous nucleation principle foaming, concrete preparation method is as follows:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 5 parts of tween-80, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 1200r/min, adds 3 parts of silicon-dioxide (particle diameter is 10 μm) in the mixture of step (1) gained, continues to stir 5min;

(3) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (2) gained, add 6 parts of oxalic acid and 3 parts of ammonium chlorides, continues to stir 5min;

(4) by mixture obtained for step (3), pour in the mould of preheating, rapid sealed mold, through microwave foaming (power is 800W) 3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, namely demoulding feeding obtains the described melamine foamed plastic based on the foaming of heterogeneous nucleation principle.The surface sweeping Electronic Speculum figure of gained froth product as shown in Figure 2.

As seen from Figure 2, when adding the nucleator of 3%, cell morphology becomes uniform smooth, the ability of opposing external force significantly improves, through measuring its abscess spacing between 0.1-0.26mm, 90% concentrates between 0.1-0.2mm, and Average Cell spacing is 0.14mm.From 0.09-0.52mm not etc., mean cell diameter is 0.23mm to cell diameter, and the highest have the cell diameter of 40% between 0.1-0.2mm; After above-mentioned analysis shows to add nucleator, cell morphology changes a lot, and manhole is through in spheroid foam structure unit, and the effect of nucleator makes abscess more easy-formation, and degree of uniformity improves.

The preparation method of described expandability melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 50%; 80 DEG C of solubilisings are warming up to after adding 3% urotropine.

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, 10% aqueous sodium hydroxide solution is added, adjust ph to 8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:3;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction about 2h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.The solid content of above-mentioned expandability melamine resin is 62%, and viscosity is 4000mPas.

Embodiment 3

Based on a melamine foamed plastic for heterogeneous nucleation principle foaming, concrete preparation method is as follows:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 10 parts of Viscotrol C polyvinyl ethers, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 1200r/min, adds 6 parts of titanium dioxide (particle diameter is 24 μm) in the mixture of step (1) gained, continues to stir 5min;

(3) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (2) gained, add 9 parts of tosic acid, continues to stir 5min;

(4) by mixture obtained for step (3), pour in the mould of preheating, rapid sealed mold, through microwave foaming (power is 800W) 3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, namely demoulding feeding obtains the described melamine foamed plastic based on the foaming of heterogeneous nucleation principle.The scanning electron microscope (SEM) photograph of gained froth product as shown in Figure 3.

As seen from Figure 3, when adding the nucleator of 6%, cell morphology is equally comparatively even, its abscess spacing from 0.10mm to 0.24mm not etc., the abscess spacing of 75% is distributed between 0.1-0.2mm, at 0.1-0.47mm not etc., mean cell diameter is 0.28mm to its cell size, has the cell diameter of 35% to be distributed between 0.2-0.3mm.

The described preparation method issuing melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 55%; 80 DEG C of solubilisings are warming up to after adding 4% urotropine.

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, 10% aqueous sodium hydroxide solution is added, adjust ph to 8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:3;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction about 1.5h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.The solid content of above-mentioned expandability melamine resin is 66%, and viscosity is 5000mPas.

Embodiment 4

Based on a melamine foamed plastic for heterogeneous nucleation principle foaming, concrete preparation method is as follows:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 7 parts of polyoxyethylene glycol, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 1200r/min, adds 9 parts of hollow glass microbeads (particle diameter is 40 μm) in the mixture of step (1) gained, continues to stir 5min;

(3) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (2) gained, add 9 parts of sulfocarbolic acids, continues to stir 5min;

(4) by mixture obtained for step (3), pour in the mould of preheating, rapid sealed mold, through microwave foaming (power is 800W) 3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, namely demoulding feeding obtains the described melamine foamed plastic based on the foaming of heterogeneous nucleation principle.The scanning electron microscope (SEM) photograph of gained froth product as shown in Figure 4.

As seen from Figure 4, after adding the nucleator of 9%, foam structure is tending towards even further, its abscess spacing from 0.08mm to 0.26mm not etc., the abscess spacing of 70% is distributed between 0.1-0.2mm, at 0.1-0.39mm not etc., mean cell diameter is 0.22mm to its cell size, has the cell diameter of 50% to be distributed between 0.2-0.3mm.

The described preparation method issuing melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 60%; 80 DEG C of solubilisings are warming up to after adding 5% urotropine.

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, 10% aqueous sodium hydroxide solution is added, adjust ph to 8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:3;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction about 1h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.The solid content of above-mentioned expandability melamine resin is 70%, and viscosity is 6000mPas.

Performance test: utilize Instron, 3385H universal testing machine, establishing criteria ASTMD1621-2010 carries out compression performance detection to material; The thermostability of TAQ500 thermogravimetric analyzer to material is adopted to detect; Scanning electronic microscope (su1510) is used to take pictures to foam sample.The density of foam sample is at 300kg/m ³left and right, its test result is as following table:

As can be seen from embodiment 1-4, after adding micron order Nucleating particles, the mechanical property of melamine foamed plastic and thermal property all have the raising of certain amplitude, foam aperture also reduces to some extent, this is because along with the raising of nucleator addition, foam structure is even gradually, the dispersion degree of abscess spacing and cell diameter reduces, and this effectively avoids stress concentration phenomenon when being subject to external force, and the mechanical property of foam is improved to some extent; Simultaneously use nucleator substitute or Some substitute conventional foaming agents also can make the environmental protection more of melamine foamed plastic industry.

Claims (9)

1., based on a melamine foamed plastic for heterogeneous nucleation principle foaming, it is characterized in that the parts by weight of contained raw material and each raw material are:

The preparation method of described expandability melamine resin is:

(1) 37% formaldehyde solution and paraformaldehyde powder are added in reactor, be mixed with the highly concentrated formaldehyde solution that massfraction is 45%-60%;

(2) under 30 DEG C of conditions, in the highly concentrated formaldehyde solution that step (1) is obtained, add urotropine or 10% aqueous sodium hydroxide solution, adjust ph is to 8-8.5;

(3), at 30 DEG C, under the condition constantly stirred, in the solution that step (2) is obtained, trimeric cyanamide powder is added; The mol ratio of described trimeric cyanamide and formaldehyde is 1:2.8-3.2;

(4) 80 DEG C are warming up to the speed of 10 DEG C/min after adding, isothermal reaction 1-2h, by the continuous assaying reaction degree of cloud point method;

(5), after reaction terminates, be cooled to rapidly 25 DEG C of dischargings with the speed of 20 DEG C/min for subsequent use, obtain described expandability melamine resin.

2. melamine foamed plastic according to claim 1, is characterized in that the preparation method of described melamine foamed plastic comprises the steps:

(1) be, under the condition of 25 DEG C, in 100 parts of expandability melamine resins, add 5-10 part tensio-active agent, be uniformly mixed in temperature;

(2) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 1200r/min, in the mixture of step (1) gained, add 3-10 part nucleator, continues to stir 3-5min;

(3) be 25 DEG C in temperature, rotating speed is under the stirring velocity of 2000r/min, in the mixture of step (2) gained, add 5-20 part solidifying agent, continues to stir 3-10min;

(4) by mixture obtained for step (3), pour in the mould of preheating, rapid sealed mold, through microwave foaming 1-3min, put into the curing oven 1h of 80 DEG C again, take out mold cools down to room temperature, namely demoulding feeding obtains the described melamine foamed plastic based on the foaming of heterogeneous nucleation principle.

3. melamine foamed plastic according to claim 1, is characterized in that in the process for preparation of described step (1) middle and high concentration formaldehyde solution, employing heats up and adds the method promotion paraformaldehyde powder dissolution of urotropine.

4. melamine foamed plastic according to claim 1 and 2, it is characterized in that the solid content of described expandability melamine resin is 60-70%, viscosity is 2000-7000mPas.

5. melamine foamed plastic according to claim 1 and 2, is characterized in that described tensio-active agent is one or more in silicone oil, polyoxyethylene glycol, Span-80, tween-80, Viscotrol C polyvinyl ether, polyoxyethylene block copolymer.

6. melamine foamed plastic according to claim 1 and 2, is characterized in that described nucleator is one or more in calcium carbonate, silicon-dioxide, titanium dioxide, hollow glass microbead; The particle diameter of described nucleator is 8 ~ 48 μm.

7. melamine foamed plastic according to claim 1 and 2, is characterized in that described solidifying agent is organic acid or organic acid salt compounds.

8. melamine foamed plastic according to claim 7, is characterized in that described solidifying agent is one or more in dilute hydrochloric acid, dilute sulphuric acid, oxalic acid, sulfocarbolic acid, ammonium chloride, tosic acid.

9. melamine foamed plastic according to claim 2, is characterized in that described microwave foaming power is 300-800W.