CN102612534A

CN102612534A - Reresin foamed sheet

Info

Publication number: CN102612534A
Application number: CN2010800518966A
Authority: CN
Inventors: 岩田正义; 古木俊信
Original assignee: Sekisui Plastics Co Ltd
Current assignee: Sekisui Kasei Co Ltd
Priority date: 2009-11-18
Filing date: 2010-11-15
Publication date: 2012-07-25
Anticipated expiration: 2030-11-15
Also published as: TW201134664A; KR20120116406A; WO2011062141A1; MY159154A; CN102612534B; TWI500512B; JP2011105863A; JP5642957B2

Abstract

Provided is a resin foamed sheet that is suitable for uses such as the formation of foam-molded products with three-dimensional structures, whereby striped patterns are inhibited from appearing on the surface of the resin foamed sheet by an approach other than adjusting extrusion conditions. The provided resin foamed sheet is formed by extruding (from an extruder) and foaming a polypropylene resin composition consisting primarily of a polypropylene resin. Said polypropylene resin composition is characterized by containing a high-melt-tension polypropylene resin in an amount constituting at least 20% and less than 50% of the contained polymer components, by mass.

Description

Resin foamed sheet

Technical field

The present invention relates to resin foamed sheet through utilizing forcing machine that polypropylene-based resin composition is extruded and foamed and form.

Background technology

In the past, the resin combination foaming was widely used in the purposes of requirement light weight and resiliency for flaky resin foamed sheet.

Wherein, the resin foamed sheet that is formed by the polypropylene-based resin composition that with the polypropylene-based resin is staple is because less expensive and extensively be used.

Usually; Through being extruded and foam, polypropylene-based resin composition makes such resin foamed sheet continuously; Not only make the resin foamed sheet of individual layer foamed resin layer, also be manufactured on the resin foamed sheet that the surface has the non-foamed resin layer that is known as thin film layer etc.

This resin foamed sheet directly is used to the buffering sheet material of sheet glass etc. with sheet, in addition, when utilizing the sheet forming method to make the foam molded product that foaming pallet etc. has three-dimensional arrangement, also use as starting material.

Thereby; Making method for such foam molded product is being carried out various researchs; For example; Put down in writing in the following patent documentation 1 through making polypropylene-based resin composition contain high melt tension acrylic resin more than the 50 quality % (below, be also referred to as " HMS-PP "), can obtain the excellent resin foamed sheet of formability.

In addition; When with the resin foamed sheet forming process during for foaming pallet etc.; Extensively adopt following forming method: make it under the remollescent state at the heating resin foamed sheet; Utilize negative pressure (being evacuated) to make resin foamed sheet be adsorbed in the vacuum forming of the shaping mould that forms the pallet shape, perhaps utilize malleation resin foamed sheet to be pushed on the forming method of pressing empty moulding that is called as of shaping mould.

In such vacuum forming, the empty moulding of pressure; Control resin foamed sheet around and form concavo-convex at this resin foamed sheet; Therefore working as resin foamed sheet is not the state of whole homogeneous, for example, and when there be in uneven thickness the grade in resin foamed sheet; Preferentially extend the position that is prone to the thin thickness of elongation owing to stress, and the moulding article produce bad order or on the moulding article, form rent sometimes.

In addition, it is the state of homogeneous that the resin foamed sheet that not only is provided in forming process needs resin foamed sheet, and directly using with sheet under the situation of resin foamed sheet also needs this item.

But, make whole homogeneous of resin foamed sheet difficult, when through extruding and foaming when forming resin foamed sheet, feel such as surface luster does not coexist to extrude on the direction and occurs with the striped apperance on the surface of resin foamed sheet continuously sometimes.

And most situation of seeing such striped on the surface of resin foamed sheet, the thickness of not only apparent on the surface luster distinct portions, sheet material or density (foam degrees) etc. are also different knifeedge.

Therefore, usually, when resin foamed sheet produces such striped, compare with the resin foamed sheet that produces striped to the surface unconfirmed, its possibility that in vacuum forming, the empty moulding of pressure, produces unfavorable condition is high, therefore requires to prevent the generation of such striped.

But, as the method that prevents this striped, also do not establish so far, main only in the countermeasure of implementing symptomatic therapy property.

For example, adopt following countermeasure, promptly; Rule of thumb; Select difficulty or ease to produce the extrusion condition of striped, begin to carry out extruding and foaming of polypropylene-based resin composition, if on the resin foamed sheet of extruding, see striped; Then further finely tune extrusion condition and find out condition that cannot see striped, thereby adopt product.

So, in the past, except that the adjustment of extrusion condition, do not establish the concrete method that is used to prevent striped, therefore, sometimes only can be in limited condition and range the preparing resin foam sheet.

Patent documentation 1: TOHKEMY 2003-236961 communique

Summary of the invention

The present invention puts in view of the above-mentioned problems and carries out, and its purpose is, through realizing suppressing the generation of striped with the approach beyond the adjustment extrusion condition, and then, realize providing the resin foamed sheet that can easily manufacture state that cannot see striped.

In order to solve above-mentioned problem, the result who has carried out intent research, the inventor find to realize suppressing the generation of striped through the composition of the polypropylene-based resin composition that uses is processed the composition of regulation, thereby have accomplished the present invention.

Promptly; Resin foamed sheet of the present invention is characterised in that; Be to be the polypropylene-based resin composition of staple with the polypropylene-based resin composition, extrude and foam and the resin foamed sheet that forms with forcing machine, wherein; In above-mentioned polypropylene-based resin composition, become more than the 20 quality % and the mode that is lower than 50 quality % contains high melt tension acrylic resin with ratio shared in the component of polymer that contains.

Among the present invention, because the high melt tension acrylic resin of component of polymer is decided to be the ratio of regulation, so when extruding with forcing machine and foaming, can be implemented on the resin foamed sheet of acquisition and be difficult to produce striped.

Therefore, extrusion condition broadens, and can obtain the second best in quality resin foamed sheet simply.

In view of the above; The resin foamed sheet of homogeneous can be provided; Thereby when utilizing vacuum forming or press the general sheet forming method of empty moulding etc. to give the spatial structure, the moulding article that can be provided at acquisition are gone up the low resin foamed sheet of possibility that produces bad order etc.

Description of drawings

Fig. 1 is the sectional view of the structure of the related resin foamed sheet of this embodiment of expression.

Fig. 2 is the synoptic diagram of formation of the manufacturing installation of the related resin foamed sheet of this embodiment of expression.

Fig. 3 is the sectional view of the structure of expression interflow mould.

Fig. 4 is the synoptic diagram of the formation operation of expression " striped ".

Embodiment

Below, as resin foamed sheet, represent that for example the resin foamed sheet with stepped construction comes embodiment of the present invention is described, this stepped construction is will be as the upper layer and the range upon range of structure of foamed resin layer of non-foamed resin layer.

As shown in Figure 1, the resin foamed sheet 1 of this embodiment has the non-foamed resin layer (upper layer 11,12) on the surface that constitutes upper face side and following side respectively and the trilaminar stepped construction that is formed at the foamed resin layer 20 between them.

That is, the resin foamed sheet 1 of this embodiment is situated between by this foamed resin layer 20 and has non-foamed resin layer (upper layer 11,12) in its both sides.

It is that the polypropylene-based resin composition of staple forms non-foamed state that this

upper layer

11,12 all utilizes with the polypropylene-based resin.

In the resin foamed sheet 1 of this embodiment; The upper layer 12 of the upper layer 11 of the upside in the front view of Fig. 1 (below be also referred to as " first surface layer 11 ") and downside (below be also referred to as " second surface layer 12 ") there is no need to make its formation consistent, also can make thickness separately different.

In addition, above-mentioned foamed resin layer 20 is to being that the polypropylene-based resin composition of staple is extruded and foamed and forms with the polypropylene-based resin through the method stated after utilizing.

And, above-mentioned upper layer the 11, the 12nd, the polypropylene-based resin composition that will be used to form them through the method for stating after utilizing forms with the above-mentioned polypropylene-based resin composition co-extrusion that is used to form above-mentioned foamed resin layer 20.

Usually, the employed polypropylene-based resin composition of formation of above-mentioned

upper layer

11,12 and above-mentioned foamed resin layer 20 is respectively the composition that is applicable to separately, therefore uses the different each other compsns of forming.

In this embodiment; For for the employed polypropylene-based resin composition of the formation of above-mentioned foamed resin layer 20, the shared ratio of high melt tension acrylic resin (HMS-PP) is more than the 20 quality % and is lower than 50 quality % in the component of polymer that is importantly contained.

As this HMS-PP; Can use the irradiation that utilizes activation-energy-rays such as electron rays to carry out the cut-out of molecule, crosslinked and form the resin of free terminal chain, perhaps utilize chemically crosslinked to come to form the free terminal chain and give the resin of high melt tension at intramolecularly at intramolecularly.

In addition,, also can use following resin, that is, import the olefin block of polyethylene block etc., utilize the block copolymerization materialization of olefin block and Vestolen PP 7052 block to give the resin of high melt tension to intramolecularly as HMS-PP.

As except that this polypropylene-based resin HMS-PP, can enumerate the sym-propene polymer resin (PP) that reality only is made up of the propylene composition.

In addition, whether be HMS-PP for polypropylene-based resin, not merely be the difference on the molecular structure of above-mentioned that kind, usually, can judge through its melt tension.

In this specification sheets, so-called high melt tension acrylic resin (HMS-PP) is meant that melt mass flow rate (MFR:melt mass flow rate) is that 0.5g/10 minute ~ 10g/10 minute, melt tension are the resin of 5cN ~ 50cN.

And this MFR is the A method according to JIS K7210 (1999), under 230 ℃ of test temperatures, load 21.18N (2.16kgf) condition, measure, and " melt tension " specifically can be measured through following.

That is,, the test portion polypropylene-based resin is accommodated in the barrel (cylinder) of the internal diameter 15mm that vertical direction disposes for " melt tension "; And with 230 ℃ temperature heating 5 minutes and make it fusion, afterwards, insert piston from the top of barrel; Utilize this piston; With the extruded velocity is 0.0773mm/s (constant), from the kapillary of the lower end that is arranged at barrel (mould footpath: 2.095mm, mould is long: 8mm; Flow into angle: wire ground resin melt extrusion 90 degree (circular cone)), can measure thus.

Particularly, thread that this is extruded volume be hung on above-mentioned capillaceous below configuration the tension force detection wheel and after passing through, use the rolling of rolling cylinder, can measure thus.The initial velocity at rolling initial stage is made as 4mm/s, acceleration afterwards is made as 12mm/s ², gently accelerate rolling speed, rolling speed that will be when the tension force of observing through the tension force detection wheel sharply reduces is as " breaking point speed ", will observe this " breaking point speed " before maximum tension conduct " melt tension " and can measure.

In addition; In this specification sheets; Even imported the segmented copolymer of olefin block with mode with melt tension to a certain degree; But its value based on the melt tension of said determination does not reach above-mentioned value, then will be in this embodiment uses as the HMS-PP of the regulation amount in the polypropylene-based resin composition yet.

Below; Term for " segmented copolymer ", " block PP "; Short of special record, the value of just being used as the melt tension in the segmented copolymer with olefin block and Vestolen PP 7052 block do not reach the meaning of the resin of above-mentioned value (suitable with " HMS-PP ") and use.

As the concrete example of the HMS-PP of the value that is above-mentioned melt tension, for example, can enumerate the resin of selling with trade(brand)name " WB130HMS ", " WB135HMS " and " WB140HMS " of Borealis company.

In addition, as the concrete example of HMS-PP, can enumerate the resin of selling with trade(brand)name " Pro-fax F814 " of Basell company.

And,, can also enumerate the resin of selling with trade(brand)name " FB3312 ", " FB5100 ", " FB7200 " and " FB9100 " of Japan Polypropylene Corporation as the concrete example of HMS-PP.

Wherein, From can easily improving through extruding and the aspect of the foam degrees when forming foamed resin layer 20 of foaming etc., the preferred trade(brand)name " WB135HMS " etc. of utilizing chemically crosslinked and forming the Borealis company of free terminal chain at intramolecularly that adopts.

With this HMS-PP in the component of polymer that polypropylene-based resin composition contained with more than the 20 quality % and the ratio that is lower than 50 quality % to comprise be that important reasons is; If HMS-PP shared ratio in component of polymer integral body is more than the 50 quality %; Then this polypropylene-based resin composition is being extruded and when foaming and preparing resin foam sheet, be easy to generate striped.

In addition; The lower value of HMS-PP is that the reason of 20 quality % is; If HMS-PP is the amount that is lower than it, then be difficult to make the polypropylene-based resin composition foaming, thereby the selecting range that might be used in the extrusion condition that obtains salable product becomes narrower with good state.

From such viewpoint, the amount of the HMS-PP in the all-polymer composition is preferably more than the 25 quality % and is lower than 50 quality %, is more preferably 30 quality % ~ 45 quality %.

In addition, comprise this HMS-PP whole polypropylene-based resins the total amount, in the all-polymer composition of the polypropylene-based resin composition that is used to form foamed resin layer 20 shared ratio, be generally more than the 80 quality %, be preferably more than the 90 quality %.

Except that this polypropylene-based resin; As the resin that is used to constitute component of polymer; Be preferably the polymkeric substance high, for example can enumerate polyvinyl resin, ethylene-ethyl acrylate copolymer resin, ethylene-vinyl acetate copolymer resin, polybutene resin, gather-thermoplastic elastomer (TPO) of polyolefin-based resins such as 4-methylpentene-1 resin and polyolefin with the intermiscibility of polypropylene-based resin.

In addition, in the polypropylene-based resin composition that is used to form above-mentioned foamed resin layer 20, except above-mentioned component of polymer, contain the composition that is useful on foaming usually.

As this composition that is used to foam; For example, can enumerate the gaseous constituent that under extrusion temperature, becomes gaseous phase, become the nucleator of nuclear when utilizing this gaseous constituent to form bubble, generation thermolysis and produce the thermolysis type whipping agent etc. of gas under extrusion temperature.

As the above-mentioned gas composition, can enumerate propane, butane, aliphatic hydrocarbons such as pentane, nitrogen, carbonic acid gas, water etc.

In addition, these gaseous constituents can be used separately, also can be also with a plurality of.

As above-mentioned nucleator; For example, can enumerate organic compound particles such as inorganic compound particles such as talcum, mica, silicon-dioxide, zeyssatite, aluminum oxide, titanium oxide, zinc oxide, Natural manganese dioxide, Marinco H, white lake, calcium hydroxide, salt of wormwood, lime carbonate, magnesiumcarbonate, vitriolate of tartar, permanent white, granulated glass sphere, tetrafluoroethylene etc.

For example can utilize the master batch method to make this nucleator be contained in the formation material of foamed resin layer; Use makes above-mentioned nucleator be scattered in the master batch of matrix resin with the arbitrary ratio in the scope of 5 quality % ~ 50 quality %, thereby can increase the effect for the usage quantity performance of nucleator.

And,, for example, can enumerate the mixture of Cellmic C 121, sodium hydrogencarbonate and sodium hydrogencarbonate and Hydrocerol A etc. as the whipping agent of thermal degradation type.

For the whipping agent of this thermal degradation type, master batchization also can improve its effect through making it to be scattered in matrix resin with the arbitrary ratio in the scope of 10 quality % ~ 50 quality %.

In addition; In the polypropylene-based resin composition that is used to form foamed resin layer 20; Can contain various additives with the resin combination that is used to form general rosin products identically, for example, can suitably contain inhibitor, inhibitor, processing aid etc.

In addition; For the related resin foamed sheet 1 of this embodiment; It in situation about directly utilizing as the fender of sheet glass or forming process situation of general foaming pallet such as display container etc. as lean meat, fresh fish etc. etc. with plate shape; In most cases, requirement can suppress by static cause charged.

Therefore, preferably in the polypropylene-based resin composition that is used to form

upper layer

11,12, contain the nonionic static inhibitor.

As this nonionic static inhibitor, for example, can enumerate alcohol is that static inhibitor, ether are that static inhibitor, ester are that static inhibitor, ester ether are static inhibitor etc.

And as above-mentioned nonionic static inhibitor, for example, can enumerate amine is that static inhibitor, acid amides are the static inhibitor of nitrogenous types such as static inhibitor.

With respect to component of polymer 100 mass parts that polypropylene-based resin composition comprised, this nonionic static inhibitor is contained in polypropylene-based resin composition with the ratio of 0.5 mass parts ~ 5.0 mass parts usually.

As above-mentioned alcohol is static inhibitor, for example, can enumerate polyoxyethylene glycol (perhaps polyoxyethylene), gather (ethylene oxide)-gather polyalkylene oxides such as (propylene oxide) block copolymerization zoarium etc.

In addition, in the above-mentioned pure type static inhibitor, the polymerization degree of oxirane is generally 1 ~ 300 (for example being 5 ~ 200), is preferably 10 ~ 150 (for example being 10 ~ 100).

Be more preferably about 15 ~ 50.

As above-mentioned ether is static inhibitor, for example, can enumerate Voranol EP 2001s such as T 46155 Octyl Ether, polyoxyethylene laurel ether, T 46155 cetyl ether; Polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octyl phenyl ether, T 46155 nonylplenyl ether etc.

As above-mentioned ester is static inhibitor; For example; Can enumerate the polyhydric alcohol fatty acid ester of the ester etc. of polyvalent alcohols such as terepthaloyl moietie, Ucar 35, TriMethylolPropane(TMP), glycerine, (gathering) glycerine, tetramethylolmethane, sorbitol anhydride, Sorbitol Powder, sucrose and lipid acid; For example, can enumerate sorbitan carboxylic esterses such as glycerol fatty acid ester, sorbitan mono-oleic acid ester such as Zerol, sucrose fatty esters such as sucrose monostearate etc.

As above-mentioned ester ether is static inhibitor, for example, can enumerate T 46155 glycerol fatty acid esters such as polyoxyethylene glycerol stearate, T 46155 oleic acid glyceride; Polyoxyethylene sorbitan carboxylic esters such as polyoxyethylene sorbitol acid anhydride stearate; Polyoxyethylene polyols fatty esters such as T 46155 sucrose fatty ester.

In addition, for example, can enumerate Witconol 5909 and T 46155 and solidify the castor-oil plant wet goods.

As the static inhibitor of above-mentioned nitrogenous type, for example, can enumerate the polyoxyethylene alkyl amine that has the alkyl structure of carbon number about 6 ~ 24 in the molecule of T 46155 laurylamine etc.; The polyoxyethylene fatty acid acid amides that has the fatty acid structure of carbon number about 6 ~ 24 in the molecule of polyoxyethylene 8 stearate acid amides etc.; N-alkanol alkylamines such as N-ethanol alkylamine, perhaps N, N such as N-di-alcohol alkylamine, alkanol alkylamines such as N-alkanol alkylamine; N-alkanol fatty acid amides such as N-ethanol stearic amide, perhaps N, N such as N-di-alcohol stearic amide, alkanol fatty acid amides such as N-alkanol fatty acid amide.

In addition, as the alkyl, the lipid acid that constitute above-mentioned nonionic static inhibitor, can enumerate the material of carbon number about 6 ~ 24 usually.

Lipid acid can be enumerated unsaturated fatty acidss such as sfas (for example, the sfas of carbon numbers such as capric acid, LAURIC ACID 99 MIN, TETRADECONIC ACID, palmitinic acid, Triple Pressed Stearic Acid 6 ~ 24), oleic acid.

In addition, on this nonionic static inhibitor, can and be that static inhibitor, positively charged ion are that static inhibitor, both sexes are static inhibitor, polymer static inhibitor also with negatively charged ion; As the low molecule-type static inhibitor of above-mentioned negatively charged ion system; AS etc. can be enumerated,, tetraalkylammonium salt etc. can be enumerated as the low molecule-type static inhibitor of positively charged ion system; As the low molecule-type static inhibitor of both sexes system, can enumerate alkyl betaine etc.

In addition; As above-mentioned polymer static inhibitor, can enumerate the multipolymer of polyoxyethylene, polyoxytrimethylene, polyoxyethylene glycol, polyesteramide, polyetheramides plasma cross-linked polymer or its quaternary ammonium salt and polyethers-polyolefin block polymer ethylene series blocks such as (polyethers are the segmented copolymer of block and polyolefin block) and wetting ability block etc.

So-called nonionic static inhibitor, negatively charged ion are that static inhibitor, positively charged ion are that static inhibitor, both sexes are the static inhibitor of the low molecule-type of static inhibitor; In time, ooze out on the surface of resin foamed sheet 1, produces to be known as the phenomenon of " (bleed out) exosmoses " and to bring into play anti-static function.

Therefore, in the polypropylene-based resin composition that is used to form

upper layer

11,12, preferably contain above-mentioned nonionic static inhibitor, and contain the composition that exosmoses that is useful on this nonionic static inhibitor of promotion.

As the composition that exosmoses that promotes this nonionic static inhibitor, any in ethene-alpha-olefin copolymer or the ldpe resin and percent crystallinity are that 20% ~ 55% resin especially produces effect.

In the polypropylene-based resin composition that is used to form

upper layer

11,12, can contain a kind in this ethene-alpha-olefin copolymer or the ldpe resin separately, also can contain multiple.

In addition, also can the ethene-alpha-olefin copolymer more than a kind be mixed with ldpe resin more than a kind, assign to utilize as the one-tenth that exosmoses that promotes the nonionic static inhibitor.

In addition, in order to promote exosmosing of nonionic static inhibitor, in the component of polymer of polypropylene-based resin composition, their total amount is preferably more than the 20 quality %, is more preferably more than the 25 quality %.

In addition, the upper limit is generally about 40 quality %, and their total amount is preferably below the 35 quality %.

The percent crystallinity of this ethene-alpha-olefin copolymer or ldpe resin can be measured according to JISK7121:1987 " the tansition temperatures measuring methods of plastics ".

Particularly; Can use differential scanning calorimeter (DSC) device " DSC6220 type " of SII NanoTechnology corporate system, measuring the about 7mg test portion of container filling, under the condition of nitrogen flow 30ml/min; Intensification (cooling) speed intensification (cooling) with 10 ℃/min; And, from the starting point of point that baseline leaves, be their terminal point with the point that is back to baseline once more for melting (crystallization) with the DSC curve; Mensuration is melted heat and crystallization heat, utilizes following formula to try to achieve percent crystallinity.

Percent crystallinity (%)=(crystallization heat (mJ)/crystalline melts heat (mJ) fully) * 100

(wherein, fully crystallization to melt heat (theoretical value) be 285.7mJ/mg.）

The component of polymer of polypropylene-based resin composition can be only by above-mentioned HMS-PP be used to promote that the composition that exosmoses of this nonionic static inhibitor constitutes; And, can to these suitably add polypropylene-based resin beyond the HMS-PP that explains as the formation material of above-mentioned foamed resin layer 20, with high ethylene series resin, the TPO of affinity of this polypropylene-based resin.

In addition, because this polypropylene-based resin composition constitutes the surface of resin foamed sheet 1, be useful on the various additives that performance will make the function that this surface possesses so can contain as required.

For example, can perhaps improve oilness through containing the deterioration that weather resisting agent, inhibitor prevent resin foamed sheet 1 or foaming pallet through containing lubricant.

Perhaps, can realize the raising attractive in appearance that causes through painted through containing pigment.

In addition; In the resin foamed sheet 1 of this embodiment; As the variable thickness phasing separately of first surface layer 11 and second surface layer 12 with, the cooperation content of the polypropylene-based resin composition that in the formation of first surface layer 11 and second surface layer 12, uses also can be different.

For example, can be only a side in the outside of the pallet that is equivalent to foam contain pigment and implement paintedly, and a side of the inboard of the pallet that will be equivalent to foam is made as Natural color (perhaps white).

In addition, above-mentioned nonionic is the side that static inhibitor etc. also can only be contained in the outside of the pallet that is equivalent to foam, and does not contain being equivalent to an inboard side.

The thickness of each layer of the first surface layer 11 of such resin foamed sheet 1, second surface layer 12 and foamed resin layer 20 is not special to be limited, but first surface layer 11 or second surface layer 12 are generally any the thickness in the scope of 50 μ m ~ 150 μ m.

In addition, foamed resin layer 20 forms any the thickness in the scope of 0.5mm ~ 5.0mm usually, and density (apparent density) is 0.15g/cm ³~ 0.6g/cm ³

Can use the forcing machine that generally in the manufacturing of resin foamed sheet, uses to implement extruding and foaming of above-mentioned polypropylene-based resin composition, thereby make such resin foamed sheet 1.

Below, with reference to Fig. 2, Fig. 3, the method for manufacture of resin foamed sheet 1 is described in further detail.

In addition, Fig. 2 is the brief configuration figure of the manufacturing installation of resin foamed sheet, and Fig. 3 is the sectional view of appearance of the inside of expression interflow mould (Reference numeral XH) shown in Figure 2.

In addition, Fig. 4 is that expression is extruded polypropylene-based resin composition and the figure of the appearance that foams, and the appearance of the part represented by the dotted line A of Fig. 2 of expression.

The manufacturing installation of the resin foamed sheet that this is shown in Figure 2 possesses as first forcing machine 70 of tandem forcing machine and as the forcing machine of 2 series of second forcing machine 80 of single axle forcing machine.

In addition, in these forcing machines, have: be used for interflow mould XH that the resin combination behind the melting mixing is collaborated; And circular die CD, it has the circular squit hole that is used for the resin combination tubular ground ejection behind this interflow mould XH interflow.

And this manufacturing installation has: the resin foamed sheet to the ejection from circular die CD tubular ground carries out gas cooling refrigerating unit CL; Be used for the resin foamed sheet hole enlargement of this tubular and become the plug MD of tubular of the size of regulation; To add the cutting device (not shown: among Fig. 2 only the appearance cut apart up and down of expression) that is divided into 2 sheet materials along the otch of extruding direction through the resin foamed sheet behind this plug MD; The rolling cylinder 92 that after making resin foamed sheet 1 after cutting, is used to carry out rolling through a plurality of cylinders 91.

Above-mentioned first forcing machine 70 is used to form foamed resin layer 20; Swim above that on the forcing machine (below be also referred to as " upstream side forcing machine 70a ") of side, be provided with the hopper 71 that is used to drop into the polypropylene-based resin composition that forms foamed resin layer 20, the gas importing portion 72 that is used in barrel, supplying with gaseous constituents such as hydrocarbon.

And; Downstream side at this upstream side forcing machine 70a; Have forcing machine (below be also referred to as " downstream side forcing machine 70b "), it is used for the polypropylene-based resin composition that contains the above-mentioned gas composition (below be also referred to as " foamable resin compsn ") is carried out melting mixing and to interflow mould XH ejection.

In addition; Above-mentioned second forcing machine 80 is used to form first surface layer 11 and second surface layer 12; It constitutes; Be used for forming the polypropylene-based resin composition (below be also referred to as " non-foamable resin compsn ") of upper layer from hopper 81 input with the state of non-foaming, inner at barrel, this non-foamable resin compsn is carried out melting mixing and to interflow mould XH ejection.

Shown in the concise and to the point sectional view of Fig. 3, above-mentioned interflow mould XH is formed with: the first resin stream W1, and its right side from the front view of Fig. 3 connects central part towards the left side; The second resin stream W2, it is used at this first resin stream W1 midway, and resin is flowed in this first resin stream W1; The 3rd resin stream W3, it is used on the upstream side of this second resin stream W2 (the front view right side of Fig. 3), and resin is flowed in this first resin stream W1.

The above-mentioned second resin stream W2 forms; Resin combination is flowed into to resin stream W1 from the circular slit S1 at the wall opening that forms resin stream W1; Above-mentioned the 3rd resin stream W3 forms; The body P that disposes opening end with central part at the above-mentioned first resin stream W1 is connected, and resin combination is flowed into to the central part of the first resin stream W1.

The above-mentioned first resin stream W1 swims side above that and is connected with first forcing machine 70; The downstream side is connected with circular die CD; Above-mentioned second resin stream W2 and above-mentioned the 3rd resin stream W3 are connected with second forcing machine 80 via distribution piping D, so that can flow into non-foamable resin compsn from second forcing machine 80.

Promptly; The interflow mould XH of this embodiment constitutes; Can become the columned resin flow of 3 weight structures of non-foamable resin compsn/foamable resin compsn/non-foamable resin compsn in the downstream side of the first resin stream W1, supply with these resins towards circular die CD.

And; Circular die CD forms; Can make the columned resin combination rheology of 3 weights that mould XH flows into from the interflow (being " non-foaming system resin combination "/" foamable resin compsn "/" non-foaming system resin combination " from the center toward the outer side) turn to cylindraceous flowing, with them from circular squit hole coextrusion.

When utilizing such device to come the preparing resin foam sheet; For example can enumerate following method: at first; Drop into the polypropylene-based resin composition that is used to form foamed resin layer 20 from the hopper 71 of first forcing machine 70; And drop into the polypropylene-based resin composition that is used to form

upper layer

11,12 to second forcing machine 80, in each forcing machine, implement melting mixing, afterwards from circular die CD coextrusion with the temperature more than the melt temperature of resin.

In addition, for each resin combination, can make each one-tenth be divided into the admixture of homogeneous in advance,, also can in forcing machine, mix from different hopper inputs afterwards to the hopper input.

In these forcing machines, because therefore composition that need melting mixing is used to foam first forcing machine 70 in is pressed into gaseous constituent from the gas importing portion 72 that is located at upstream side forcing machine 70a, enforcement mixes with molten resin.

Can implement through following mode from the coextrusion of above-mentioned circular die CD: will forcing machine 70b is adjusted into and is suitable for the temperature extruding and foam in the downstream side at the foamable resin compsn of the upstream side forcing machine 70a of first forcing machine 70 melting mixing; Mould XH carries to the interflow; On the other hand; In second forcing machine 80; Non-foamable resin compsn is adjusted into the temperature of the formation that is suitable for first, second

upper layer

11,12, and mould XH carries to the interflow, thereby the stepped construction based on molten resin is formed in the mould XH of interflow in advance.

And then; To in the mould XH of interflow, form the foam cylindraceous of stepped construction by each polypropylene-based resin composition from the circular squit hole coextrusion of circular die CD by each resin combination behind the interflow with foamed resin layer 20 and

upper layer

11,12.

Afterwards; With above-mentioned foam along the periphery of the diameter plug MD bigger and circumferentially extending than the squit hole of circular die CD; And to its cooling; Utilize cutter (not shown) that cooled foam up and down 2 is cut apart and processed zonal resin foamed sheet 1, rolling is on cylinder 92 respectively.

At this moment, owing in the polypropylene-based resin composition that is used to form foamed resin layer 20, contain HMS-PP, so can be extruded with good foamed state.

In addition, above-mentioned foam cylindraceous produces the increase of the thickness that accompanies with the increase of foam degrees after ejection, thereby apparent volume is expanded.

In addition, this foam not only expands in the thickness direction upper volume, upwards also produces volumetric expansion in week.

In addition, because of the power that pulls that cylinder 92 causes, above-mentioned foam cylindraceous moves along the direction of plug MD, is accompanied by this and moves and gently carry out hole enlargement with the mode near the external diameter of plug MD.

Therefore, as shown in Figure 4, if the circumferential speed of expansion after extruding is being carried out below the speed of hole enlargement this foam FB, the possibility that problem then takes place is low, and common near circular die CD, forms flaccid part FE because speed of expansion is high at foam FB.

Promptly; If the circle that being assumed to be the circle of being described with the squit hole of circular die CD is upper base, described with the end face MDa towards the plug MD of this circular die CD is the horizontal truncated cone shape of going to the bottom; Then among the foam FB between circular die CD and the plug MD; The position FT that the power that pulls that cylinder 92 causes acts on (below be also referred to as " tension portion FT "); With along the form of the lateral inclination of above-mentioned truncated cone shape at circular die CD to moving between plug MD, and above-mentioned flaccid part FE, through above-mentioned side also inboard and at circular die CD to mobile between plug MD.

And under such situation, usually, form a plurality of flaccid part FE, become the state that alternately forms at make progress in week flaccid part FE and tension portion FT near the circular die CD at this foam FB.

In addition, the volumetric expansion of foam FB is tightened up in the position of leaving a little from circular die CD usually, and because the carrying out of hole enlargement and flaccid part FE is applied circumferential tension force, thus with plug MD near the position on, can not observe lax usually.

But; During this; During till eliminating flaccid part FE; The extension that flaccid part FE and tension portion FT are applied, the contact method (cooling conditions) of cooling air create a difference, and on sheet thickness, density etc., difference take place, and on through the resin foamed sheet after the plug MD, form because the striped apperance that the existence of above-mentioned flaccid part FE and the FT of mentioned strain portion causes.

For the polypropylene-based resin composition of this embodiment, because the amount of HMS-PP has been stipulated the upper limit, so the foaming movement relaxes, the volumetric expansion after extruding from circular die CD is gentle.

Therefore, be difficult to produce big relaxing at foam FB, to the roughly effect equably that extends on the whole that foam FB applies, cooling conditions is also roughly even, so can suppress striped.

In addition, if the amount of HMS-PP is lower than lower value, then as stated, be difficult to become good foamed state.

In addition; Through the speed of pulling (resin foamed sheet in the unit time rolling in the length of cylinder 92) is accelerated; The speed of foam FB being carried out hole enlargement can be improved, thereby on certain kind degree, the inhibition of striped can be realized, but because above-mentioned volumetric expansion is to produce moment; Therefore compare with the amount of the HMS-PP that adjusts polypropylene-based resin composition, the inhibition effect of striped is little.

In addition, if it is too high to pull speed, then also can produce big tension force to foam FB, amount that therefore we can say the HMS-PP through polypropylene-based resin composition is realized the inhibition of striped, belongs to more easy method.

In addition, this pulls speed according to the kind of the resin foamed sheet of making, thickness etc. and different, is generally 2m/ minute ~ 10m/ minute.

In addition; Equally; Bore (d1: the inboard circle of ejiction opening and the middle circular diameter between the circle of the outside) through making circular die CD is big with ratio (d2/d1) change of the profile (d2) of plug MD; Thereby increase also is being fine on certain kind degree to suppressing striped along circumferential extension, but effect at this moment is still less with the comparison that under the situation of the amount of adjusting HMS-PP, obtains.

In addition, usually, this ratio (d2/d1) is 1.9 ~ 3.2, and the slot gap of circular die CD is selected in the scope of 0.3mm ~ 1.5mm usually.

Further, to a certain extent also can the movement of control volume expansible through the adjustment whipping agent, but if exceedingly reduce the amount of whipping agent, then there is resin foamed sheet can't be possible of good foamed state naturally.

From such viewpoint, we can say that the amount that utilizes HMS-PP realizes that the method for the inhibition of striped is easy method.

In addition, usually, whipping agent is 1 mass parts ~ 6 mass parts with respect to the ratio of component of polymer 100 mass parts for example under the situation of using butane (n-butane, i-butane or their mixed solution).

The thickness and the foamed state of the resin foamed sheet of so making become homogeneous.

In addition; In

upper layer

11,12; Percent crystallinity is that 20% ~ 55% ethene-alpha-olefin copolymer or percent crystallinity are that 20% ~ 55% ldpe resin is involved with the nonionic static inhibitor, so this nonionic static inhibitor can promptly exosmose on the surface.

Through so, under the normal temperature, for example, make surface resistivity be reduced to 1 * 10 ¹³Below Ω/, thereby can bring into play antistatic property.

Therefore; Need not be set to curing time till the performance of desirable antistatic property etc., perhaps, even be provided with also can be between short-term in completion; Therefore resin foamed sheet can realize shortening the time in the storehouse of this resin foamed sheet just using between short-term after the manufacturing.

In addition, such resin foamed sheet because its rerum natura obtained homogenizing, thus when utilizing sheet forming method etc. to carry out forming process, produce partial extension and on the moulding article possibility of generation " bad order ", " breaking " low.

That is, favourable for the yield rate that improves the moulding article.

In addition; If the surface at resin foamed sheet forms striped, it is inhomogeneous that the thickness of this resin foamed sheet becomes, and then the part of thicker contacts with shaping mould at first; Its result, the static inhibitor that exosmoses in this part does not move to the part that contacts with the shaping mould brute force easily.

And in the sheet forming method, resin foamed sheet is a heated condition, so the movability of static inhibitor is also high, if resin foamed sheet in uneven thickness, then might and not have the position of static resistance in the dense position of the surface of moulding article formation static inhibitor.

That is, when

upper layer

11,12 being contacted with shaping mould and make the moulding article, we can say that the resin foamed sheet of this embodiment can be used particularly well with the sheet forming legal system.

In addition; In this embodiment; For example expression have the two sides that covers foamed resin layer upper layer 3-tier architecture resin foamed sheet and embodiment of the present invention is illustrated; But for the stepped construction that has more than 4 layers, above-mentioned polypropylene-based resin composition is extruded and foamed and when forming foamed resin layer performance and above-mentioned striped inhibition effect of giving an example identical too with forcing machine.

The situation about only forming in the single face side of foamed resin layer for upper layer in addition, and the situation of individual layer foamed resin layer also are identical.

And, for the situation of a plurality of foamed resin layers of co-extrusion, also can be through utilizing the polypropylene-based resin composition of this embodiment, the inhibition effect of performance striped.

In addition; Though omit further detailed description at this; But for resin combination and extrude and technological item that foaming technique or resin foamed sheet and method of manufacture thereof etc. are related in known item, in the scope of significantly not damaging effect of the present invention, all can adopt the present invention.

Embodiment

Next enumerate embodiment and come the present invention is described in further detail, but the present invention does not limit to therewith.

(embodiment 1)

During the preparing resin foam sheet, used with device shown in Figure 2 to constitute equipment of the same race.

Promptly; On two positions in the upstream side of the resin stream W1 of the foamable resin compsn that flows into from first forcing machine 70 and downstream side; So that flow into the mode of non-foamable resin compsn via arm D from second forcing machine 80; First, second forcing machine is connected with interflow mould XH, and the downstream side of mould XH connects circular die CD and has implemented coextrusion at this interflow.

At first; As first forcing machine of the formation material that is used for the melting mixing foamed resin layer, having prepared by bore is that the single shaft forcing machine (upstream side forcing machine) of 90mm and the bore that is connected with this single shaft forcing machine are the tandem type forcing machine that the single shaft forcing machine (downstream side forcing machine) of 115mm constitutes.

And then; To contain with the HMS-PP that sells as trade(brand)name " WB135 " by Borealis company be 39 quality %, the block PP that sold as trade(brand)name " BC6C " by Japan Polypropylene Corporation is 55 quality %, the TPO that sold as trade(brand)name " Q-100F " by SunAllomer company is the ratio of polymer composition of 6 quality %; And be to be that the sodium hydrogencarbonate-Hydrocerol A of 0.5 mass parts is whipping agent (the corporate system master batch of refining big day under the situation of 100 mass parts with the total amount of these component of polymer; Trade(brand)name " Finecell MasterPO410K ") foamed resin layer forms the polypropylene-based resin composition of usefulness; Upstream the bore of side is the hopper supply of the single shaft forcing machine of 90mm; And in this forcing machine, carry out heating and melting with 200 ℃～210 ℃ temperature; Be pressed into butane (Trimethylmethane/normal butane=35/65 quality %) afterwards,, carry out mixing so that become 4 mass parts with respect to the ratio of these molten resin 100 mass parts as gaseous constituent.

With the forcing machine supply of side downstream of this foamable resin compsn, the temperature of foamable resin compsn is reduced, supply with to the interflow mould XH that is connected with the forcing machine front end with 120kg/ hour spray volume.

On the other hand, as second forcing machine of the formation material that is used for the melting mixing upper layer, prepared the single shaft forcing machine of bore 65mm.

And then; To contain with the HMS-PP that sells as trade(brand)name " WB135 " by Borealis company be 70 quality %, (percent crystallinity: the ethene-alpha-olefin copolymer of 26%) selling is the ratio of polymer composition of 30 quality % as trade(brand)name " KS240T " by Japan Polypropylene Corporation; With total amount with these component of polymer is to be nonionic static inhibitor (KAO. Corp. SA's system of 2.0 mass parts under the situation of 100 mass parts; Trade(brand)name " TS-2B ") upper layer forms the polypropylene-based resin composition of usefulness; Hopper to second forcing machine is supplied with, and carries out heating and melting with 200 ℃ temperature.

Next; After the distribution piping with branch's stream is divided into two parts with (non-lathering property) polypropylene-based resin composition of this molten state; From the body of the central part opening of the resin stream of mould with at the slot two of the peripheral part opening of resin stream at the interflow; It with separately total amount 15kg/ hour amount ejection; After the internal layer side and the range upon range of interflow of outer layer side of foamable resin compsn; From circular die (bore 140mm, gap, slit 1.0mm) the cylindric ground coextrusion with 135kg/ hour resin spray volume that is connected with interflow mould front end, thereby both sides form the range upon range of foam cylindraceous that the upper layer of non-foaming is arranged across foamed resin layer and within it.

This is extruded and foams and the foam cylindraceous made places diameter: the cooling of 414mm * length: 500mm is with on the plug and carry out hole enlargement; And; Its outside is blown air and cooled off from air-dry apparatus; 2 of weeks at this plug upwards symmetric (open 180 degree) utilize cutter to cut, thereby process 2 zonal resin foamed sheets.

For the resin foamed sheet of the embodiment 1 that obtains, measured surface resistivity based on JIS K 6911-1995.In addition, the pre-treatment time is made as measured in 24 hours.

Particularly, with the test specimen of the limit plane square that is 10cm after the environment held of 22 ℃ of temperature, humidity 60% 24 hours, under the environment of 22 ℃ of temperature, humidity 60%; With testing apparatus (Advantest corporate system; Numeral ultra-high resistance/small electric flowmeter R8340 and Resistivity Chamber R12702A), to the load crimping electrode of test specimen, and apply the voltage of 500V with about 30N; Measure resistance value after spending 1 minute, calculate through following formula.

ρs=π（D＋d）/（D－d）×Rs

Wherein,

ρ s: surface resistivity (Ω/)

D: the internal diameter (cm) (being 7cm among the Resistivity Chamber R12702A) of the ring electrode on surface

D: the external diameter of the interior circle of surface electrode (cm) (being 5cm among the Resistivity Chamber R12702A)

Rs: surface resistivity (Ω)

Result viewing is to 3.5 * 10 ¹²The value of the surface resistivity of Ω/.

In addition, on this resin foamed sheet, do not observe tangible striped.

And then, made the foaming pallet with the sheet forming method, its outward appearance is beautiful and physical strength is also excellent.

(embodiment 2)

In being used to form the polypropylene-based resin composition of upper layer; Replace the ethene-alpha-olefin copolymer (KS240T) of Japan Polypropylene Corporation system and used new LDPE (film grade) (PE) resin of the percent crystallinity 50% of selling as trade(brand)name " LD400 " by Japan Polypropylene Corporation; In addition; Make resin foamed sheet with embodiment 1 identically, and made the foaming pallet.

To the resin foamed sheet of this embodiment 2, measure the result of surface resistivity with embodiment 1 identically, have 5.0 * 10 ¹²The surface resistivity of Ω/.

In addition, do not observe tangible striped, and the outward appearance of the foaming pallet that is formed by this resin foamed sheet is beautiful and physical strength is excellent.

(embodiment 3)

In being used to form the polypropylene-based resin composition of upper layer; Replace the ethene-alpha-olefin copolymer (KS240T) of Japan Polypropylene Corporation system and used new LDPE (film grade) (PE) resin of the percent crystallinity 53% of selling as trade(brand)name " LF441B " by Japan Polypropylene Corporation; In addition; Make resin foamed sheet with embodiment 1 identically, and made the foaming pallet.

For the resin foamed sheet of this embodiment 3, measure the result of surface resistivity with embodiment 1 identically, have 6.5 * 10 ¹²The surface resistivity of Ω/.

(embodiment 4)

In being used to form the polypropylene-based resin composition of upper layer; Replace the ethene-alpha-olefin copolymer (KS240T) of Japan Polypropylene Corporation system and use ultra-low density polyethylene (PE) resin of the percent crystallinity 36% of selling as trade(brand)name " EXCELLEN VL-100 " by Sumitomo Chemical Co. Ltd.; In addition; With embodiment 1 identical ground preparing resin foam sheet, and made the foaming pallet.

For the resin foamed sheet of this embodiment 4, measure the result of surface resistivity with embodiment 1 identically, have 4.0 * 10 ¹²The surface resistivity of Ω/.

In addition, do not observe tangible striped, the outward appearance of the foaming pallet that is formed by this resin foamed sheet is beautiful and physical strength is excellent.

(embodiment 5)

The ratio of HMS-PP in the polypropylene-based resin composition that is used to form foamed resin layer (WB135) is replaced with 25 quality % from 39 quality %; And correspondingly change the ratio of block PP (BC6C) into 69 quality % from 55 quality %; In addition; Make resin foamed sheet with embodiment 1 identically, and made the foaming pallet.

For the resin foamed sheet of this embodiment 5, measure the result of surface resistivity with embodiment 1 identically, have 3.5 * 10 ¹²The surface resistivity of Ω/.

(embodiment 6)

In being used to form the polypropylene-based resin composition of upper layer, component of polymer is made as HMS-PP (WB135) 100 quality %, in addition, make resin foamed sheet identically, and made the foaming pallet with embodiment 1.

For the resin foamed sheet of this embodiment 6, measure the result of surface resistivity with embodiment 1 identically, be 4.5 * 10 ¹³The surface resistivity of Ω/.

In addition, originally do not observe tangible striped on one's body, and the outward appearance of the foaming pallet that is formed by this resin foamed sheet is beautiful and physical strength is excellent at resin foamed sheet.

(embodiment 7)

In being used to form the polypropylene-based resin composition of upper layer, do not contain the nonionic static inhibitor, in addition, make resin foamed sheet identically, and made the foaming pallet with embodiment 1.

For the resin foamed sheet of this embodiment 7, measure the result of surface resistivity with embodiment 1 identically, be 6.5 * 10 ¹⁵The surface resistivity of Ω/.

(embodiment 8)

In being used to form the polypropylene-based resin composition of upper layer, do not contain the nonionic static inhibitor, in addition, make resin foamed sheet with embodiment 5 identically, and made the foaming pallet.

For the resin foamed sheet of this embodiment 8, measure the result of surface resistivity with embodiment 1 identically, be 6.5 * 10 ¹⁵The surface resistivity of Ω/.

(comparative example 1)

The ratio of HMS-PP in the polypropylene-based resin composition that is used to form foamed resin layer (WB135) is replaced with 18 quality % from 39 quality %; And correspondingly the ratio with block PP (BC6C) changes 76 quality % into from 55 quality %; In addition; Make resin foamed sheet with embodiment 1 identically, and made the foaming pallet.

For the resin foamed sheet of this comparative example 1, measure the result of surface resistivity with embodiment 1 identically, have 3.5 * 10 ¹²The surface resistivity of Ω/.

But resin foamed sheet does not have foaming for enough thickness, though do not observe tangible striped, the physical strength of the foaming pallet that is formed by this resin foamed sheet is compared relatively poor with the situation of each embodiment.

(comparative example 2)

The ratio of HMS-PP in the polypropylene-based resin composition that is used to form foamed resin layer (WB135) is replaced with 50 quality % from 39 quality %; And correspondingly the ratio of block PP (BC6C) being changed into from 55 quality % is 44 quality %; In addition; Make resin foamed sheet with embodiment 1 identically, and made the foaming pallet.

For the resin foamed sheet of this comparative example 2, measure the result of surface resistivity with embodiment 1 identically, have 3.5 * 10 ¹²The surface resistivity of Ω/.

But the striped of resin foamed sheet is obvious, and on the foaming pallet that is formed by this resin foamed sheet, finds that perforate is bad, is difficult to obtain the foaming pallet of good surface appearance.

The result of study of above embodiment, comparative example is shown in following comparison sheet (table 1).

Table 1

Know from above-mentioned,, can provide and suppress resin foamed sheet striped, that be suitable as formation material with three-dimensional arrangement foam molded product according to the present invention.

Description of reference numerals:

1 ... Resin foamed sheet

11 ... First surface layer (non-foamed resin layer)

12 ... Second surface layer (non-foamed resin layer)

20 ... Foamed resin layer

Claims

1. a resin foamed sheet is characterized in that, is with being the polypropylene-based resin composition of staple with the polypropylene-based resin, extrude and foam and the resin foamed sheet that forms with forcing machine, wherein,

In said polypropylene-based resin composition, become more than the 20 quality % and the mode that is lower than 50 quality % contains high melt tension acrylic resin with ratio shared in the component of polymer that contains.

2. resin foamed sheet according to claim 1, wherein, said high melt tension acrylic resin has the free terminal chain that forms through chemically crosslinked.

3. resin foamed sheet according to claim 1 and 2; Wherein, Possesses non-foamed resin layer on the surface; And have range upon range of extrude and the foam foamed resin layer that forms and the stepped construction of said non-foamed resin layer through said polypropylene-based resin composition, and said non-foamed resin layer is to utilize the polypropylene-based resin composition that contains the nonionic static inhibitor to form.

4. resin foamed sheet according to claim 3; Wherein, In forming the polypropylene-based resin composition of said non-foamed resin layer, further contain percent crystallinity and be 20% ~ 55% ethene-alpha-olefin copolymer or percent crystallinity and be 20% ~ 55% ldpe resin.

5. according to claim 3 or 4 described resin foamed sheets, be used under heating condition, implementing forming process and said non-foamed resin layer being contacted with shaping mould and implements the purposes of said forming process.