RU2123018C1 - Composition for making plastic foams - Google Patents

Abstract

FIELD: chemistry of polymers. SUBSTANCE: composition comprises binder, surfactant, aluminium powder and acid-type foaming-hardening agent. Phenol binder is essentially resol-type liquid phenol resin prepared by reacting diphenyl propane with formaldehyde in the presence of alkali metal hydroxide. Composition based plastic foams have reduced shrinkage, elevated working temperatures and are ecologically pure and not easily combustible. The composition comprises desired additives. EFFECT: improved properties of the composition. 2 cl, 2 tbl

Description

 The invention relates to the production of foams based on phenolic binders, in particular on the basis of diphenylolpropane, which can be widely used for the manufacture of heat and sound insulating and other products from foams and are used in various fields of the national economy, for example, when laying insulating heating mains, in civil and housing (thermal insulation of walls, roofs, as the middle layer of reinforced concrete panels, etc.), for thermal insulation of vehicles, etc.

 Phenolic foams are very widely known in the foam industry and are produced on the basis of both novolac and resol phenolic binders, as well as their various modifications (including the use of special additives).

 However, in the light of recent environmental requirements, they do not meet modern requirements.

 So, in the US, the use of phenolic foams in housing is prohibited.

 For all phenolic foams, the main significant drawback is the presence of free phenol in their composition, and over a wide range (up to 25%). This is especially true for industrial domestic brands of polystyrene foam, produced at the present time.

 Phenol is a nerve poison that has both a strong local irritating and cauterizing effect. Wastewater containing phenol is very difficult to treat. During the processing, free phenol easily volatilizes, polluting the environment and leading to poisoning and numerous occupational diseases.

 Therefore, it is obvious that developments aimed at creating phenolic-free foams by using new binders that do not contain free phenol are currently the most relevant.

 However, products must retain the inherent benefits of phenolic materials.

 Foams are known (US patent 4176216, C 08 J 9/14, 1980) based on a phenolic resin of a certain composition, a blowing agent - halocarbon, chlorofluoroalkane, a traditional surfactant and an acid catalyst (organic sulfonic acid mixed with inorganic sulfonic acid). However, these foams are made from harmful compounds (phenolic binder + halogen-containing foaming agents), which affects the ecology of their production and operation.

 Known foam foams (Japan, application acc. 5-8935, C 08 J 9/14, 1989) based on a phenolic resin, a foaming agent, a foaming regulator and an acid hardener, which use halogenated alkyl acid phosphates in an amount of 10-40 weight parts . Foams have good fire resistance, smoke generation, etc. However, they are toxic, i.e. contain free phenol and halogenated phosphates, and in large quantities (up to 40 g per 100 g of phenolic resin). In addition, they adversely affect the corrosion resistance of the foam and its mechanical characteristics.

 Known compositions for foams (USSR, AS 1775417, C 08 J 9/06, 1992) based on phenolic binder, surfactant, aluminum powder, foaming-curing agent VAG-3 and filler - ash, defined composition introduced to improve water absorption, combustibility.

 However, these components do not satisfy environmental requirements, since contain phenolic binder and ash, which pollutes mechanically production communications. These compositions do not provide high operating temperatures.

 A known composition for foams (USSR, AS 757559, C 08 J 9/06 1980) based on a phenolic resin modified by the bottom residue of phenol production by the cumene method (the main component of which is cumyl phenol), aluminum powder, and a surfactant and foaming-curing agent (VAG-3). However, this is a very toxic phenolic foam, as the original binder contains 7-10% free phenol. In addition, it additionally contains a more toxic compound of the styrene type (cumylphenol, L-methylstyrene-dimer in significant amounts up to 40% by weight). It is known that toxic substances in combination with each other enhance their effect.

 In addition, all the properties of these foams are slightly higher than the known foams such as FRP-1, FRP-2, Rezopen, etc.

 The closest technical solution to the proposed one is a technical solution (Vorobev V.A., Andrianov R.A. Polymeric heat-insulating materials. M., 1972, p. 219-225), in which foams of FRP grades based on widely known phenol-formaldehyde resins are proposed, for example, brands FRV-1, FRV-1A, combined with a surfactant (surfactant-OP-7 and OP-10) - 1.0-3.0 wt. hours and aluminum powder - 1.0-3.0 wt.h, foaming and curing agent VAG-3 - 20-25 wt.h.

However, in addition to the fact that these compositions are toxic, because emit free phenols and formaldehyde, they have insufficient physical and mechanical properties, such as shrinkage, operating temperatures, etc. Phenolic foam FRP-1 falls into the category of slow-burning only with a density of 90 kg / cm ³ and higher.

 An object of the invention is to improve the environment in the production and operation of foams, as well as reduce shrinkage and increase operating temperatures without compromising the basic, necessary properties.

This goal is achieved in that the composition for producing foams, including a phenolic binder, a surfactant, aluminum powder and an acid-type foaming-curing agent, contains as a binder a liquid resol resin obtained by the interaction of diphenylolpropane and formaldehyde in the presence of alkali metal hydroxide during their molar ratio 1: 1,2-3,0-0,0065-0,3 respectively, with molecular weight M _z 3000-6200, conditional viscosity of 250-1000 seconds, with the following ratio of the components of the composition by weight. .:
binder - 100
surfactant - 0.5-5.0
aluminum powder - 0.5-5.0
acid-type foaming-curing agent - 10-35
In addition, the composition may contain target additives in an amount of 0.1-40 wt.h.

 As target additives, a filler in an amount of 1-30 parts by weight, a hydrophobizing additive in an amount of 0.1-5 parts by weight, thermosetting resins in an amount of 0.1-15 parts by weight can be used. and other well-known additives that are used both individually and in combination with each other.

The proposed binder is an oligomeric liquid resole polycondensation product of diphenylol propane (1 mol), formaldehyde (1.2-3.0 mol) and alkali metal hydroxide (0.0065-0.3 mol) with a molecular weight of M _z 3000-6200 ( determined by the method of sedimentation, Tsvetkov V.E., Frenkel F. Ya. "The structure of macromolecules in solutions", Nauka, Moscow, 1944, pp. 421-494), with a nominal viscosity of 250-1000 sec, dry residue 60 90%, viscous liquid from light yellow to light brown.

A binder is obtained in a reactor equipped with a mixing device, a thermometer, a manometer and other necessary devices and devices. Download 1.2-3.0 moles of 35-40% concentration of formaldehyde (formalin, better than 37% concentration) and with stirring, enter 0.0065-0.3 moles of alkali metal hydroxide (dry or in the form of solutions of the desired concentration) and 1 mol of diphenylol propane (DPP). Next, the reaction mixture is heated to a temperature of 70-100 ^o C and at this temperature the mixture is condensed 90-150 minutes. After that, a vacuum is created in the reactor (0.5-0.9 kg / cm ² ) and the concentration process is carried out with continuous stirring of the product to a nominal viscosity of 250-1000 sec (using a VZ-246 viscometer, ⌀ 6 mm). Next, the binder is cooled to a temperature of 30 ± 5 ^o C and poured into storage containers.

 The surfactant and blowing agent can be added directly to the binder at the end of the concentration step.

The proposed binder has the following characteristics:
1. Conditional viscosity on the VZ-246 viscometer, ⌀ 6 mm, sec. - 250-1000
2. Conditional viscosity on the viscometer VZ-246, ⌀ 6 mm, sec (the binder contains a surfactant and a foaming agent) - 150-900
3. Mass fraction of solids,% - 60-90
4. The molecular weight M _z for sedimentation - 3000-6200
5. The content of free formaldehyde,% - ≤0.8
6. The rate of foaming - 10-30
7. Induction foaming period - 70-280
As diphenylolpropane (bisphenol A), any bisphenol A can be used, in particular, technical grades A, B, B.

 As formaldehyde use 35-40% solutions in water, preferably 37% concentration.

 As alkali metal hydroxide, sodium hydroxide or potassium is used (dry or diluted to 40-50% concentration before use).

 As aluminum powder, any known powder can be used, for example, grades PAP-1, PAP-2, PAP-4 and others.

 As a surfactant, for example, products of processing a mixture of mono- and dialkylphenols with ethylene oxide (excipients OP-7 and OP-10), polyacetoglycol, organosilicon compounds and others can be used.

 Hydrochloric acid, phosphoric acid, VAG-1 (a mixture of hydrochloric and phosphoric acid with urea), VAG-2 (diethylene glycol solution of a mixture of sulfophenol and phosphoric acid), VAG-3 (aqueous solution of sulfofen condensation product with formaldehyde mixed with phosphoric acid), mixtures thereof, etc.

 As the filler, any inorganic particulate fillers can be used, for example, ground silica sand, chalk and others.

 As hydrophobizing additives, any known compounds used in foams as hydrophobizing, for example, organosilicon compounds, for example, grades GKZh-11, GKZh-94, GKZh-92 and others, can be used.

 Urea, melamine, and epoxy resins can be used as thermosetting resins, both pure and modified, both individually and in mixtures.

 The process for preparing foam compositions consists in simple mechanical mixing under normal conditions of the appropriate amounts of components, except a foaming-curing agent, for 10-20 minutes in any administration sequence, and, as mentioned above, surfactants and aluminum powder can be introduced into the binder at the production stage, at the end of the concentration stage.

 Then, the resulting composition is filled in the cavity of the molds or structures and foaming is carried out in the free foaming mode or under pressure, or in the combined mode, depending on the required properties.

 The invention is illustrated by the following examples.

Example A
97.3 kg (1.2 moles) of formalin (37%, GOST 16725-89) are loaded into a reactor equipped with a stirrer, a thermometer, a monovacuometer, a refrigerator and a jacket for heating and cooling, and 0.65 kg (0) with stirring , 0065 mole) 40% sodium hydroxide solution (GOST 2263-79). When the stirrer is working, 228 kg (1 mol) of DFP (GOST 12138-86) are loaded into the reactor. The mixture is stirred until the DPP is dissolved. Next, the reaction mixture is heated to (77 ± 2) ^o C by supplying steam to the jacket and maintaining the temperature for 2 hours, supplying steam or water as necessary to the jacket. At the same time, the refrigerator operates in the “reverse mode”. Then the refrigerator is switched to “direct” and gradually a vacuum is created in the reactor. The concentration process is carried out with continuous stirring and a vacuum of 0.7 kg / cm ² for 1 hour. In the process of distillation of water periodically reduce the vacuum for sampling and determination of viscosity. The first sample is taken 15 minutes after the appearance of water and then vacuum until a viscosity of 250 seconds is obtained.

The resulting binder is cooled to a temperature of (30 ± 5) ^o C with a working mixer and poured into storage tanks.

 The binder has the characteristics shown in table 1.

Example B
Get a binder according to the scheme described in example A. Download 121.9 kg of 36.9% formalin (1.5 mol) and 6 kg (0.15 mol) of dry alkali NaOH. Then, 114 kg (0.5 mol) of diphenylol propane are added with stirring.

The mixture is heated to 87 ^° C. Condensation is carried out for 1 hour 20 minutes.

Concentration is carried out under a vacuum of 0.5 kg / cm ² to a viscosity of 700 seconds.

Then the reaction mass is cooled to (20 ± 5) ^o C. The resulting binder has the characteristics shown in table 1.

Example B
A resol binder is synthesized according to the scheme of Example A. 100 kg of 40% formalin (1.33 mol) are loaded and, with stirring, 10 kg of 50% alkali NaOH (0.125 mol). When the stirrer is working, add 228 kg (1 mol) of DPP, stirring is carried out until it dissolves. Raise the temperature of the mixture to (90 ± 5) ^o C by supplying steam and maintain it for 1 hour 45 minutes.

Then, the product is concentrated for 1 hour under vacuum of 0.75 kg / cm ² to a viscosity of 650 sec.

The reaction mass is cooled to (25 ± 5) ^o C. Further, 1.64 kg (0.5 parts by weight) per 100 parts by weight are added with stirring. binder) OP-7 (GOST 8433-87) and 1.64 kg of aluminum powder PAP-4 (GOST 5494-71) (0.5 parts by weight per 100 parts by weight of binder).

 After loading the components, exposure is carried out for 0.5 hours and the contents of the reactor are poured into storage tanks.

 Characteristics of the obtained binder are shown in table 1.

Example D
In a three-necked flask equipped with a stirrer, reflux condenser, and thermometer, 97.3 g (1.2 mol) of 37% formalin are charged. With stirring, 228 g (1 mol) of diphenylolpropane are added. Next, turn on the heating and enter 224 g of a 50% alkali solution - KOH (0.2 mol). At a temperature of (90 ± 5) ^o C, the mass can withstand 1 hour 40 minutes. A vacuum is connected and water is distilled off for 40 minutes (vacuum = 0.6 kg / cm ² ) to a viscosity of 900 sec. The reaction mass is cooled to a temperature of (25 ± 5) ^o C. Then, 17.4 g of OP-7 product (5 parts by weight of OP-7 per 100 parts by weight of a binder) is introduced into the reaction mass with stirring and continuing stirring 17 4 g of aluminum powder PAP-4 (5 parts by weight of powder per 100 parts by weight of a binder).

 The finished binder has the characteristics shown in table 1.

 Example 1

A binder (1 kg) with a molecular weight of M _z = 1000, obtained according to example B, is combined with stirring with 5 g of OP-10 (0.5 wt.h.) and 5 g of aluminum powder PAP-2 (0.5 wt. hours) within 10 minutes. Then add the curing agent VAG-3 - 350 g (35 parts by weight). The composition is stirred for 30 seconds and poured into a mold whose temperature is (25 ± 5) ^o C. The mold is closed and kept for 10 minutes to undergo foaming and curing. Then the manufactured samples are disassembled and removed. The characteristics of the foam are shown in table 2.

 Example 2

Resole binder (100 kg) with M _z = 3000, obtained according to example A, is mixed with 5 kg of OP-7 and 5 kg of aluminum powder PAP-1 (5 parts by weight per 100 parts by weight of binder) for 15 minutes and sent to consumables working alternately. From consumable tanks, a binder with compressed air (pressure 0.7 atm) is piped into the mixing chamber of the filling machine. The foaming-curing agent VAG-3 25 kg (25 parts by weight per 100 parts by weight of binder) through another pipeline similarly to the binder also enters the mixing chamber. The number of separately supplied components in a predetermined ratio is controlled by the opening time of the shut-off valves.

 Mixing of the components in the chamber is carried out by a propeller stirrer with n = 1500 rpm.

 Filling of the foam composition is carried out from the mixing chamber into molds mounted on an annular conveyor. Products are removed from the conveyor in the form of hollow cylinders. The resulting foam has the characteristics shown in table 2.

 Example 3

A binder of 1 kg with M _z = 5100 obtained in example B, including 0.5 wt. hours OP-10 and 0.5 wt. including aluminum powder PAP-2 per 100 parts by weight binder, combine with stirring and when heated to (25 ± 2) ^o C with the product VAG-3 (TU6-05-1116-78) in an amount of 100 g (10 parts by weight) for 40 seconds.

The finished composition is poured into a warm mold, the temperature of the mold is 30 ^° C. The mold is closed and held for 15 minutes to undergo foaming and curing. Then the form is taken apart. The resulting foam is tested. The characteristics of the foam are shown in table 2.

 Example 4

1 kg of the binder obtained according to example G (M _z = 6000) containing 5 wt. hours OP-7 and 5 parts by weight PAP-4 powders at a temperature of 30 ^o C are combined with stirring with 250 g of VAG-3 (25 parts by weight per 100 parts by weight of binder) for 30 seconds. The composition is poured into a mold, which is then closed and incubated for 20 minutes. Then the form is disassembled and the test of the obtained foam is carried out. The properties are shown in table 2.

 Example 5

In a binder (1 kg) obtained in example A, with M _z = 3000, 30 g of PAG-1 polyacetoglycol (3 parts by weight), 20 g (2 parts by weight) of PAP-2 aluminum powder and GKZh-94 hydrophobizing liquid - 50 g (2 parts by weight per 100 parts by weight of a binder) and stirred for 20 minutes.

Then in the finished mixture having a temperature of (25 ± 5) ^o C with stirring for 40 seconds add VAG-3 in an amount of 150 g (15 parts by weight per 100 parts by weight of binder).

 The composition is poured into a mold that is closed and aged for 20 minutes. Next, the form is disassembled, and the foam is tested. The characteristics of the foam are shown in table 2.

 Example 6

In a binder (1 kg) obtained according to example G (M _z = 6000) and containing 5 wt. hours OP-7 and 5 parts by weight PAP-4 powders, with continuous stirring, add chalk in an amount of 150 g (15 parts by weight per 100 parts by weight of a binder) and VAG-3 - 280 g (28 parts by weight per 100 parts by weight of a binder) and mixed for 30-40 seconds. The resulting mixture is poured into a mold, closed and held for 15 minutes. The mold is disassembled and the resulting foam is tested. The properties are shown in table 2.

 Example 7

In the binder (1 kg) obtained according to example B (M _z = 6200), with stirring, add 50 g (5 parts by weight of OP-10) and 40 g (4 parts by weight) of PAP-2 powder. Then, 150 g of KF-MT urea-formaldehyde resin (TU6-06-12-88) and VAG-3 300 g (30 parts by weight per 100 parts by weight of binder) are introduced into the mixture and mixed for 30 seconds.

 The mixture is poured into the mold, closed and held for 15 minutes. The mold is disassembled and the resulting foam is tested. The properties of the foam are shown in table 2.

 Example 8

A binder of 1 kg with M _z = 5100, obtained according to example B, including 5 g (0.5 parts by weight) of OP-10, 5 g (0.5 parts by weight) of PAP-2 aluminum powder, combined with stirring with 1 g (0.1 parts by weight) of hydrophobizing additive GKZH-11. Then add the product VAG-3 in an amount of 200 g (20 parts by weight) with mixing for 35 seconds. The composition is poured into a mold that is closed and aged for 20 minutes. Disassemble the form. Polyfoam is tested. Characteristics are given in table 2.

 Example 9

A binder of 10 kg with M _z = 3000 obtained in example A is mixed with 500 g (5 parts by weight) of PAP-1 and 500 g (5 parts by weight) of PAP-4 powder for 15 minutes. Then, with stirring, quartz sand is added in an amount of 2500 g (25 parts by weight) and 1500 g (15 parts by weight) of KF-MT urea-formaldehyde resin. Further, without stopping mixing, 3000 g (30 parts by weight) of VAG-3 are added to the composition and mixed for 20 seconds.

 The finished composition is poured into a mold, closed and held for 15 minutes.

 Polyfoam is tested. Characteristics are given in table 2.

The data presented in the examples and tables confirm that the proposed composition for foams based on a new binder containing a liquid resole resin obtained by the interaction of diphenylolpropane with formaldehyde with a molecular weight of M _z 3000-6200 and a nominal viscosity of 250-1000 sec. characterized by high operating temperatures up to 200 ^o C in combination with low shrinkage of 0.81-0.90% at 150 ^o C.

In addition, the well-known phenolic foams fall into the category of slow-burning materials only with a density of ≥ 90 kg / cm ² .

 The proposed composition allows to obtain foams with the category of "slow-burning" regardless of their density.

 This provides foams based on them with reliability and longer service life.

 The process of production and operation of the proposed materials and products based on them compares favorably with respect to environmental ecology from known phenoplasts, since it does not contain free phenol and formaldehyde, as well as other harmful compounds.

 In addition, as can be seen from the data presented, based on the proposed compositions, it is possible to produce foams in a wide range of densities, which allows us to expand the field of their use.

 The technology for the production of the composition can be carried out at well-known capacities for the production of phenolic plastics, is simple and can be carried out by all known methods, for example, in the production of laminated panels, heat-insulating segments for pipelines, etc.

 The remaining main properties of the foams based on the proposed compositions remain at the level or even slightly better than the known phenolic, which is clearly seen from the above data.

Claims (1)

1. A composition for producing foams, including a phenolic binder, a surfactant, aluminum powder and an acid-type foaming-curing agent, characterized in that it contains a resol-type liquid phenolic resin obtained by reacting diphenylolpropane with formaldehyde in the presence of alkaline hydroxide metal with their molar ratio of 1: 1.2 - 3.0: 0.0065 - 0.3, respectively, with a mol. m. 3000 - 6200 and a conditional viscosity of 250 - 1000 s in the following ratio of the components of the composition, wt. hours:
Binder - 100
Surfactant - 0.5 - 5.0
Aluminum powder - 0.5 - 5.0
Acid type foaming and curing agent - 10 - 35
2. The composition according to claim 1, characterized in that it contains the target additives in an amount of 0.1 to 40 parts by weight

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