CN1239131A

CN1239131A - Dissolving-fusing modification of EPS and process for preparing adhesive

Info

Publication number: CN1239131A
Application number: CN99109668A
Authority: CN
Inventors: 董金狮; 魏杰; 张金禄
Original assignee: 董金狮
Priority date: 1999-07-06
Filing date: 1999-07-06
Publication date: 1999-12-22

Abstract

A process for dissolving the expanded polystyrene (EPS) in new solvent and modifying the solution by cross-linking to obtain an adhesive includes quickly dissolving the EPS in non-toxic incombustible alpha-limonene as solvent, cross-linking at a certain temp to obtain cross-linked polystyrene emulsion and adding auxiliary material of ahdesive. The obtained water-proof adhesive for building decoration features no poison, flame-retarding, high adhesion and water-proof and antifreezing nature.

Description

EPS dissolves the manufacture method of modification and tackiness agent

Polystyrene foamed (Expanded Polystyrene is hereinafter to be referred as EPS) is with advantage such as its excellent in cushioning properties energy and light weight be inexpensive and be widely used as buffering, insulation, Perserving materials.Therefore the consumption of whole world EPS is tall and big millions of tons.Owing to as the most of occasions of EPS of wrapping material all being the promptly discarded rubbish that becomes after the disposable use, how rationally utilizing to reduce that environmental pollution economizes on resources simultaneously to it is the problem that must solve as early as possible that various countries' industry member and environment-friendly interface face.

The main recoverying and utilizing method of waste EPS has following several; 1. regeneration absorption method

The regeneration absorption method is broadly divided into the salvage material method and is about to depleted EPS by special reclaiming complete processing, makes it to become again polystyrene (PS) particle that can be used for injection moulding, extrusion molding or foam; The waste EPS that the energy recovery method be about to the to reclaim burning that directly or indirectly acts as a fuel is used for heating or generates electricity; Chemical recycling is about to depleted EPS through pulverizing, oiling/decomposition, fractionation and become gas, oils or other material of petrochemical complex goods raw material.2. dissolve the appearance method that subtracts

Because the EPS quality is bulk, unit weight bulky, this gives and reclaims, the transportation in the reproduction operation, stacking, processing etc. cause great difficulty and inconvenience, and is more outstanding when particularly reclaiming as the raw material of twice-laid stuff.Be head it off, the most effective way is exactly to dwindle its volume as far as possible, promptly " subtracts appearance ".

The appearance way that subtracts of EPS mainly contains two classes, one class is that the heating and melting method that comparatively generally adopts at present promptly blasts 150-200 ℃ hot blast from thermal source and makes it fusing, another kind of is exactly that the dissolution with solvents method is about to depleted EPS and is dissolved in toluene, dimethylbenzene, methylcyclohexane, the acetone etc., separates out PS or adds other auxiliary agent and directly make tackiness agent or coating etc. without separating through separation again.

The heating and melting method is used comparatively general at present, but this method makes the impurity of thermally melting sneak into wherein easily, and hot in addition bad effect makes the polystyrene degradation of recovery, thereby influences the quality of product.And the dissolution with solvents method can reclaiming go out performance with without the PS molecular structure and the almost completely the same product of performance that use, further utilization is had great benefit.

The present invention be directed to and how to carry out the research and the creation of effective recycling method about EPS at present, its characteristics are to use the new EPS that will foam such as solvent α-limonene to dissolve, and utilize properties-correcting agent that PS is carried out the various tackiness agent of cross-linking modified preparation simultaneously.Specifically describe as follows:

Generally use ring texture compounds such as aromatic series such as toluene and methylcyclohexane for the dissolving of depleted EPS, still, because the toxicity and the inflammableness of these materials are very high, the safety problem in the use is very outstanding.The present invention uses a kind of α natural, that safety performance is good-limonene equal solvent that EPS is effectively dissolved for this reason.The ability that α-limonene at room temperature dissolves EPS is almost the same with toluene, and solubleness can reach more than 40%, and the volume-diminished that can make EPS is to original below 1/20.Being sprayed at volume such as α-limonene of at room temperature using 5 milliliters is on 125 cubic centimetres the EPS, after about 30 seconds, the volume-diminished of EPS half, all dissolvings after 3 minutes.Consoluet time length is directly proportional with the concentration of α-limonene.

The flame retardant properties of α-limonene is also fine.Experiment shows, contacts with the spark of lighter or α-limonene solution of being heated to 800 ℃ iron staff and α-limonene or containing 10% polystyrene and also can not burn on firely, uses safer.

Can further prepare different tackiness agent to dissolved polystyrene.But owing to contain the phenyl ring rigidity in the molecular structure of polystyrene greatly and flexible little, very weak at the bonding force on polar material surface, the tackiness agent insufficient strength and the glue-line that directly make with polystyrene are not only crisp but also hard, need adding properties-correcting agent to carry out modification and handle.The present invention introduces on the polystyrene macromolecular chain in polar group such as the isocyanic ester-the NCO base, thereby is cross-linked with each other the formation esters polymer, makes it to polar surfaces good bonding force be arranged.The present invention selects tolylene diisocyanate the most frequently used in the isocyanic ester (TDI) as properties-correcting agent, under the effect of initiator azo-bis-isobutyl cyanide, generates polystyrene molecular chain free radical, with tolylene diisocyanate following reaction takes place:

(1) generates the macromolecular chain free radical

(2) chain free radical and TDI carry out crosslinking reaction

(R representative in the above equation

Group)

Concrete preparation process is described below:

Clean useless EPS with the dissolving of a certain proportion of α-limonene, alcohol mixed solvent, is added azo-bis-isobutyl cyanide after reaching required temperature, and isocyanic ester adds auxiliary agent behind the reaction 90min, stirs evenly, and pours out glue.Adopt orthogonal table contrived experiment prescription,, must optimum formula be through variance analysis: solvent ratio 2: 1, properties-correcting agent consumption＜1%, reaction times 90min, 80 ℃ of temperature of reaction, polystyrene is 1: 2 with the solvent quality ratio.

PS tackiness agent performance comparison is as follows after modification:

Performance	Modified adhesive	Unmodified glue
Performance	Modified adhesive	Unmodified glue	Outward appearance	The Yellow River look thick liquid	Colourless transparent liquid
Glued membrane sticking power/level shearing resistance/Mpa is water-fast bubble resistance to impact shock/Nm	1-2 〉=4 24h do not have considerable change 5	4 1.5 glued membrane major parts come off 5	Outward appearance	The Yellow River look thick liquid	Colourless transparent liquid

As can be seen, with the PS glue behind the modifier modification than unmodified PS glue no matter from adhesiveproperties, glued membrane sticking power, or all there is tangible improvement the water tolerance aspect.

Properties-correcting agent tolylene diisocyanate (TDI) is a kind of strong polar material, and its modified effect is very obvious, only needs minute quantity just can obviously improve the performance of tackiness agent.Not only PS is had modifying function preferably, and to other resin such as resol, Resins, epoxy etc. all there is good modifying function.

The effect of properties-correcting agent isocyanic ester has two aspects, and the one, in polystyrene macromolecular, introduce polar group, the 2nd, it is crosslinked that the polystyrene macromolecular chain is produced.The consumption of properties-correcting agent directly influences the character of PS.Few as consumption, then to contain polar group few for PS, and degree of crosslinking is not enough, the toughness deficiency; Too many as consumption, the crosslinked strong body structure of net that forms has excessively even reduced shearing resistance.Experiment shows, the properties-correcting agent consumption is can reach modified effect at 1% o'clock.

The selection of solvent and solvent ratio has very big influence to the quality of dissolution rate and tackiness agent.α-limonene is an apolar substance, adding an amount of polar solvent such as ethanol can make the consoluet time shorten half, experimental results show that to the ethanol that adds 4% in α-limonene to reach the optimal dissolution effect, and gained modified adhesive intensity is big, rate of drying is accelerated.

The present invention has following advantage:

1. changed the shortcoming of using poisonous inflammable benzene kind solvent and ketones solvent, use safer, few to atmospheric pollution, fire hazardous not;

2. the toughness of PS, water tolerance and intensity improve after modification is handled, with the bonding force increase of polarity material;

3. can make the tackiness agent with waterproof, moisture-proof role of different purposes by adding softening agent and filler.

4. economize on resources, the protection environment improves salvage value.

Claims

1. a polystyrene foamed (EPS) dissolves the manufacturing technology of method of modifying and tackiness agent, it is characterized in that polystyrene foamed (EPS) being dissolved and to the cross-linking modified preparation construction and decoration of lysate tackiness agent with a kind of novel nontoxic nonflammable solvent.The tackiness agent that so makes has nontoxic, nonflammable and advantage such as bonding force is strong, waterproof is freeze proof.

2. polystyrene foamed according to claim 1 (EPS) is meant various damping packings, Freshkeeping Packaging, human food snack container and building heat preservation EPS.

3. nontoxic nonflammable solvent according to claim 1 is meant natural solvent α one limonene.

4. the amount that natural solvent α-limonene according to claim 3 accounts for total component can reach 20-80%, and preferable amount is 40-70%.

5. it is that the poor solvent ethanol of EPS makes dissolution time shorten half that natural solvent α-limonene according to claim 4 can add an amount of script during EPS in dissolving, and its consumption accounts for the amount of total component can be 1-8%, and preferable amount is 3-5%.

6. according to claim 1 the used linking agent of the cross-linking modified preparation construction and decoration of lysate tackiness agent is meant in polar functionalities such as the isocyanic ester-NCO base one compounds, that the most frequently used is tolylene diisocyanate (TDI), under the effect of initiator azo-bis-isobutyl cyanide, generate polystyrene molecular chain free radical and tolylene diisocyanate generation crosslinking reaction.

7. the consumption of linking agent tolylene diisocyanate according to claim 6 (TDI) is 0.1-1.0%, and optimum amount is 0.5-0.8%.

8. add some preparation tackiness agent filler such as talcum powder and softening agent such as dibutyl phthalate etc. commonly used, the consumption interpolation routinely as required of its consumption the according to claim 1 cross-linking modified preparation construction and decoration of lysate tackiness agent is also comprised.