JPH09124739A - Styrene-acrylic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a styrene-acrylic resin compsn. excellent in moldability and light transmission properties. SOLUTION: This compsn. comprises a copolymer which is obtd. by copolymerizing a free-radical-polymerizable monomer component comprising a styrene compd. and (meth)acrylonitrile and/or a (meth)acrylic ester in the presence of a free-radical-polymn. initiator and a chain transfer agent for free- radical polymn. represented by the formula: Q[(CO)p -O- X<1> )x -A<1> -(CO)r - X<2> }m -(CO)q A<2> -Z]n (wherein Q is a polyvalent org. group; X<1> is carbonyl or CONH; A<1> and A<2> are each a 1-8C alkylene; X<2> is O, S, or NH; Z is a chain transfer group; (p), (q), (r), and (x) are each 0 or 1; (m) is an integer of 1-50 provided structures in m braces may be the same or different from each other when (m) is 2-50; and (n) is an integer of 2-100 provided structures in (n) brackets may be the same or different from each other).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a styrene-acrylic resin composition. More specifically, the present invention relates to a styrene-acrylic resin composition having a narrow molecular weight distribution, excellent moldability, and excellent light transmittance.

[0002]

2. Description of the Related Art Styrene-acrylic resins obtained by copolymerization of styrene with (meth) acrylonitrile or (meth) acrylic acid ester have a light-transmitting property and are therefore used for transparent plastic moldings and the like. There is.
However, in terms of styrene / acrylonitrile copolymer,
A weight ratio of 75/25 is the azeotropic composition. From this, in the prior art, (meth) acrylonitrile content is low, and since it is difficult to produce a styrene-acrylic resin having a high light transmittance in a high yield, when a high light transmittance is required, The (meth) acrylonitrile content was usually 25 to 35% by weight.

[0003]

However, in recent years, there has been an increasing demand for diversification of light-transmissive resins, and the light-transmissive resins pursue various improvements in various performances and physical properties depending on the purpose of use. Need to let. As the light-transmitting resin, there are polycarbonate resin, SMA resin, MS resin and the like in addition to styrene-acrylic resin, and various requirements are satisfied by compounding these light-transmitting resins or modifying the resin. Consideration is in progress. When compounding different types of resins, the point is not to reduce the compatibility and light transmittance, so the light-transmitting resin to be compounded has a high light transmittance and the range of choices to obtain compatibility is high. The wider is preferable. The present invention has been made under such a background. That is, an object of the present invention is to newly obtain a styrene-acrylic resin having a high light transmittance despite a low (meth) acrylonitrile content.

[0004]

The present inventors have arrived at the present invention as a result of extensive studies on a styrene-acrylic resin composition having a narrow molecular weight distribution by radical polymerization.
That is, the present invention provides a radical polymerizable monomer comprising styrenes (A) and (meth) acrylonitrile (B) and / or (meth) acrylic acid esters (C),
A styrene-acrylic resin composition comprising a copolymer (D) obtained by copolymerization in the presence of a radical polymerization initiator and a chain transfer agent for radical polymerization represented by the following general formula (1). General formula In the formula, Q is a polyvalent organic group, X ¹ is a carbonyl group or -C
ONH-, A ¹ and A ² are alkylene groups having 1 to 8 carbon atoms, X
² is an oxygen atom, a sulfur atom or an NH group, Z is a chain transfer group, p, q, r and x are 0 or 1 respectively, and m is 1 to 5
An integer of 0 and n are integers of 2 to 100, and may be the same or different in [] and in {} when m is 2 to 50.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, examples of the styrenes (A) include styrene, α-methylstyrene, t-butylstyrene, dimethylstyrene, acetoxystyrene, vinyltoluene and the like. Also,
(Meth) acrylonitrile (B) is acrylonitrile or methacrylonitrile. Examples of the (meth) acrylic acid ester (C) include methyl (meth) acrylate, butyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, Tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) acrylate, docosyl (meth) acrylate, etc.], hydroxypolyoxyalkylene ether mono (Meth) acrylates and the like can be mentioned.

In the general formula (1), Q is a residue obtained by removing OH from polyhydric alcohol or polyhydric phenol,
Examples thereof include a residue obtained by removing COOH from a polycarboxylic acid. As the polyhydric alcohol, alkylene glycol having 2 to 8 carbon atoms (ethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6
-Hexanediol, neopentyl glycol, etc.),
Dihydric alcohols such as diols having a cyclic group and having 5 to 10 carbon atoms; 3 carbon atoms such as glycerin, trimethylolpropane, trimethylolethane and hexanetriol
~ 12 trihydric alcohol; 4 to 20 carbon atoms such as pentaerythritol, methylglycoside, diglycerin, etc.
Alcohols having a higher number of functional groups, such as pentitols (adnitol, arabitol, xylitol, etc.), hexitols (sorbitol, mannitol, iditol, taritol, dulcitol, etc.), sugars [sucrose, monosaccharides (glucose, mannose, etc.). , Fructose, sorbose, etc.), oligosaccharides (crehalose, lactose, raffinose, etc.)]; glucosides [eg polyols (glycol,
Glucosides of glycerin, trimethylolpropane, alkanepolyols such as hexanetriol); polyalkanepolyols [eg polyglycerin such as triglycerin, tetraglycerin]; polypentaerythritol (dipentaerythritol, tripentaerythritol, etc.); cycloalkanepolyols [Tetrakis (hydroxymethyl) cyclohexanol etc.] and the like can be mentioned.

Further, polyvinyl alcohol having a degree of polymerization of up to 100 can be used.

Further, di- and triethanolamine; alkylamines having 2 to 20 carbon atoms, 2 to 6 carbon atoms
Alkylenediamines such as ethylenediamine, propylenediamine, hexamethylenediamine, polyalkylenepolyamines such as aliphatic amines such as diethylenetriamine, triethylenetetramine, aniline, phenylenediamine, diaminotoluene, xylylenediamine, methylenedianiline, diphenyletherdiamine, etc. Examples thereof include alicyclic amines such as group amines, isophoronediamine, cyclohexylenediamine, and dicyclohexylmethanediamine, and alkylene oxide adducts such as aminoethylpiperazine.

Examples of polyhydric phenols include monocyclic polyhydric phenols such as pyrogallol, hydroquinone and phloroglucin; bisphenols such as bisphenol A and bisphenol sulfone; condensates of phenol and formaldehyde (novolak) and polyphenols.

As the polyvalent carboxylic acid, divalent carboxylic acid [(1) aliphatic dicarboxylic acid having 2 to 20 carbon atoms (maleic acid, fumaric acid, succinic acid, adipic acid, sebacic acid, malonic acid, azelaic acid, Mesaconic acid, citraconic acid, glutaconic acid, etc.); (2) Alicyclic dicarboxylic acid having 8 to 20 carbon atoms (cyclohexanedicarboxylic acid, methylmedic acid, etc.); (3) Aromatic dicarboxylic acid having 8 to 20 carbon atoms (phthalate) Acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, naphthalenedicarboxylic acid, etc.);
(4) Alkyl or alkenyl succinic acid having a hydrocarbon group having 4 to 35 carbon atoms in the side chain (isododecenyl succinic acid, n-dodecenyl succinic acid, etc.), trivalent or higher carboxylic acids [(1) carbon number 7 to 20 aliphatic polycarboxylic acids (1,2,4-butanetricarboxylic acid, 1,2,5
-Hexanetricarboxylic acid, 1,3-dicarboxylic acid-
2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, etc.); (2) carbon number 9-20
Alicyclic polycarboxylic acids (e.g., 1,2,4-cyclohexanetricarboxylic acid); (3) aromatic polycarboxylic acids having 9 to 20 carbon atoms (1,2,4-benzenetricarboxylic acid, 1,2,5 -Benzenetricarboxylic acid, 2,5,7
-Naphthalene tricarboxylic acid and 1,2,4-naphthalene tricarboxylic acid, pyromellitic acid, benzophenone tetracarboxylic acid, etc.)] and the like. Further, an unsaturated polycarboxylic acid polymer having a degree of polymerization of up to 100 can be mentioned.

In the general formula (1), Z is SH,
SR, SSR, CX ₃ (R is an alkyl, aryl, aralkyl, alkoxy, aryloxy or cycloalkyl group having 1 to 20 carbon atoms, which may be substituted with a halogen atom, an alkyl group, a cyano group or a nitro group. Is a chlorine atom, a bromine atom.) And the like. Of these, SH is preferred.

In the general formula (1), p is 0 when Q is a polyhydric alcohol or polyhydric phenol residue, and p is 1 when Q is a polyhydric carboxylic acid residue. If p is 0,
x and q are 0 or 1, and r is 0. When p is 1, x is 0 and q and r are 0 or 1, respectively.

In the general formula (1), n is preferably 2 to 8 and m is preferably 1 to 30.

The chain transfer agent represented by the general formula (1) is Z
When is SH, it can be manufactured by the following method, for example. Chain Transfer Agent 1 (when p is 0, x is 0, q is 0 and r is 0) After the cyclic ether is added to the ω-mercapto-alkyl alcohol, it is etherified with the polyhydric alcohol. Alternatively, a cyclic ether is added to a polyhydric alcohol, the terminal is chlorinated with thionyl chloride or the like, and then reacted with an alkali hydrosulfide. Specific examples of chain transfer agents include polyoxyethylene glycol-di-2-mercaptoethyl ether.

Chain transfer agent 2 (p is 1, x is 0, q is 0,
When r is 0) A cyclic ether (cyclic sulfide, cyclic imine) is added to ω-mercapto-alkyl alcohol, and then esterified with a polyvalent carboxylic acid.

Chain transfer agent 3 (p is 0, x is 1, q is 1,
When r is 0) A cyclic lactone (cyclic lactam) is added to the polyhydric alcohol, and then esterified (amidated) with ω-mercapto-carboxylic acid. Specific examples of chain transfer agents include triethanolamine-ε-caprolactone adduct-tri-3-mercaptopropionic acid ester.

Chain transfer agent 4 (p is 0, x is 1, q is 0,
When r is 0) After adding a cyclic lactone (cyclic lactam) to the polyhydric alcohol, etherification (amination) is carried out with ω-mercapto-halogenide. Specific chain transfer agents include triethanolamine-ε-caprolactone adduct-tri-2
-Mercaptoethyl ether and the like.

Chain transfer agent 5 (p is 0, x is 0, q is 1,
When r is 0) After adding a cyclic ether (cyclic sulfide, cyclic imine) to the polyhydric alcohol, esterification (thioesterification, amidation) is carried out with ω-mercapto-carboxylic acid. Specific examples of chain transfer agents that can be produced by this method include the following. (1) 1-10 alkylene oxides (ethylene glycol, propylene glycol, etc.) in alkylene glycols (ethylene glycol, propylene glycol, etc.)
A product obtained by adding 0 mol and forming a diester with 3-mercaptopropionic acid at the end. Polyoxyethylene glycol (number average molecular weight 630) di-3-mercaptopropionic acid ester, polyoxypropylene glycol (number average molecular weight 600) di-3-mercaptopropionic acid ester and the like. (2) A compound in which 1 to 150 mol of alkylene oxide is added to a trihydric or higher polyhydric alcohol (glycerin, pentaerythritol, sho, etc.), and the end is formed into a diester with 3-mercaptopropionic acid. Tetra-3-mercaptopropionic acid ester of pentaerythritol ethylene oxide 20 mol adduct and the like. (3) Polyvinyl acetate (weight average molecular weight 50,000,
Esterified with 2-mercaptoacetic acid (saponification degree 10%).

Chain transfer agent 6 (p is 1, x is 0, q is 1,
When r is 0) After adding a cyclic ether (cyclic sulfide, cyclic imine) to the polycarboxylic acid, esterification (thioesterification, amidation) is carried out with ω-mercapto-carboxylic acid. Specific examples of the chain transfer agent include propylene oxide adipate 4 mol adduct-di-2-mercaptoacetic acid ester.

Chain transfer agent 7 (p is 1, x is 0, q is 0,
When r is 1) A cyclic lactone (cyclic lactam) is added to the polycarboxylic acid, and then esterified with ω-mercapto-alcohol.

Of these chain transfer agents, preferred are chain transfer agents 1 to 4, more preferred are chain transfer agents 1 and 2, and particularly preferred is chain transfer agent 1.

In the production of the above compound, it is also possible to co-add a cyclic ether and a cyclic lactone,
When co-adding, either random co-adding or block co-adding may be used. Examples of cyclic ethers include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, and styrene oxide, examples of cyclic thioethers include episulfide, and examples of cyclic imines include ethyleneimine. These may be co-added, and when co-added, either random co-addition or block co-addition may be performed. Of these, preferred are cyclic ethers, and more preferred are ethylene oxide, propylene oxide and mixtures thereof. Examples of the cyclic lactone include ε-caprolactone and δ-valerolactone, and examples of the cyclic lactam include ε-caprolactam. These may be co-added, and when co-added, either random co-addition or block co-addition may be performed.

The purpose of the chain transfer agent of the present invention is to have a plurality of chain transfer groups mutually having at least four functional groups (ether,
(Ester, amide, etc.) are present apart from each other, which makes it possible to produce a polymer having a narrow molecular weight distribution.

The amount of the chain transfer agent used in the present invention is usually 0.01 to 20% by weight, preferably 0.1 to 10%, particularly preferably 0.1 to 5%, based on the monomers. is there.

Known initiators can be used for the polymerization, and examples thereof include water-soluble azo initiators (azobisamidinopropane (salt), azobiscyanovaleric acid (salt), etc.) and oil-soluble azo. Initiators (azobiscyanovaleronitrile, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, etc.), water-soluble peroxides (hydrogen peroxide, peracetic acid, etc.), oil-soluble peroxides (benzoyl peroxide, cumene) Hydroxy peroxide, dibutyl peroxide, etc.), inorganic peroxides (ammonium persulfate,
Sodium persulfate etc.) and the like. A redox initiator system may be formed with the above-mentioned peroxide and a reducing agent, and examples of the reducing agent include bisulfite (sodium bisulfite, potassium bisulfite, ammonium bisulfite, etc.),
Examples thereof include primary amines (dimethylaminobenzoic acid (salt), dimethylaminoethanol, etc.), amine complexes of transition metal salts (pentamethylenehexamine complex of cobalt (III) chloride, diethylenetriamine complex of copper (II) chloride, etc.) and the like. Further, an azo initiator, a peroxide initiator, or a redox initiator may be appropriately used in combination. The amount of the polymerization initiator is usually 0.01 to 1 with respect to the radical polymerizable monomer.
It is 0% by weight, preferably 0.05 to 5% by weight.

In the method of producing the polymer of the present invention, the polymerization method may be any of solution polymerization, emulsion polymerization, suspension and bulk polymerization. As the solvent in the case of solution polymerization, water,
Alcohols (methanol, ethanol, isopropanol, etc.), ketones (acetone, methyl isobutyl ketone, etc.), ethers (tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, heptane, etc.), aromatic hydrocarbons (toluene, xylene) Etc.), halogenated solvents (ethylene dichloride, etc.) and mixtures thereof.

The polymerization temperature is usually 50 to 300 ° C.,
Preferably it is 100-250 degreeC. For solution polymerization,
Examples of the temperature include a temperature lower than the boiling point of the polymerization solution under normal pressure, a boiling point of the polymerization solution under normal pressure, and a temperature higher than the boiling point of the polymerization solution under pressure. Further, when a dispersion medium, an emulsifier, a dispersant, etc. are used, there is no particular limitation and known ones can be used.

The number average molecular weight of the copolymer obtained by the production method of the present invention is usually 1,000 to 500,000, preferably 3,000 to 500,000. The molecular weight distribution is usually 1.20 to 3.00, preferably 1.20.
2.50. The molecular weight distribution depends on the polymerization system,
Compared with the case where the chain transfer agent of the present invention is not used, it becomes much narrower. Here, the molecular weight distribution is (weight average molecular weight /
Number average molecular weight).

The light transmittance of the styrene-acrylic resin of the present invention is usually 85% or more, preferably 90% or more.

Since the styrene-acrylic resin of the present invention has a high light-transmitting property, it can be used for eyeglass lenses, contact lenses, image-reading lenses for copying machines and fax machines, and CDs.
-It is useful as an optical material such as a pickup lens and an optical fiber optical disk substrate.

[0031]

EXAMPLES The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. Parts in the examples are parts by weight. The method for measuring the number average molecular weight and the molecular weight distribution by GPC is as follows. Machine type: HLC-8120 (manufactured by Tosoh) Column: TSK gel Super H4000 + TSK gel Super H3000 + TSK gel Super H2000 (both manufactured by Tosoh) Column temperature: 40 ° C Detector: RI solvent: Tetrahydrofuran sample concentration: 0.25 weight % Injection volume: 10 μl Standard: Polystyrene

(Production of Chain Transfer Agent) Production Example 1 A pressure resistant reactor was charged with 680 parts of pentaerythritol and 5 parts of potassium hydroxide, and the temperature was raised to 130 ° C. after nitrogen substitution. Propylene oxide 5,85 at 110 to 130 ° C
0 part was charged and reacted for 5 hours. After aging at the same temperature for 1 hour, the mixture was cooled to 50 to 70 ° C., 160 parts of water and 60 parts of synthetic magnesium silicate were added, and the mixture was stirred for 2 hours and then filtered.
Then, dehydration was performed to obtain 6,500 parts of a pentaerythritol propylene oxide 20 mol adduct. Then
650 parts of this adduct was placed in a reaction vessel, and 520 parts of thionyl chloride was added dropwise at 80 ° C. over 4 hours while stirring. After maintaining the same temperature for 1.5 hours, 1,000 parts of a 30% sodium hydrosulfide aqueous solution was added dropwise over 5 hours. After holding at the same temperature for 2 hours, the temperature was returned to room temperature, and liquid separation was performed to obtain pentaerythritol propylene oxide adduct tetra-2-mercaptoethyl ether which is the chain transfer agent of the present invention. This is designated as chain transfer agent A.

Example 1 A flask equipped with a stirrer, a reflux condenser, two dropping funnels, a thermometer and a gas blowing port was charged with 250 parts of styrene, 50 parts of acrylonitrile, 800 parts of DMF and 1 part of a chain transfer agent A, and stirred under nitrogen. After replacement, the temperature was raised to 80 ° C. A mixture of 700 parts of styrene, 1 part of chain transfer agent A and 100 parts of tetrahydrofuran was added dropwise from one dropping funnel at the same temperature over 6 hours, and 5 parts of azobisisobutyronitrile was simultaneously added from the other dropping funnel. And 200 parts of tetrahydrofuran were added dropwise over 7 hours. After holding at the same temperature for 3 hours, the solvent and unreacted monomers were distilled off to obtain 980 parts of a styrene-acrylonitrile resin (hereinafter abbreviated as AS resin-1). The acrylonitrile content in this resin was 5.0%, the number average molecular weight was 22,000, and the molecular weight distribution was 1.8.

Comparative Example 1 A styrene-acrylonitrile resin (hereinafter referred to as AS resin-2) was prepared in the same manner as in Example 1 except that the chain transfer agent A was not used.
Abbreviated). The acrylonitrile content in this resin was 4.2%, the number average molecular weight was 23,000, and the molecular weight distribution was 2.9.

Example 2 Ethylene chloride 4 was placed in a flask equipped with a stirrer, a reflux condenser, two dropping funnels, a thermometer and a gas blowing port.
00 parts and 5 parts of the chain transfer agent A were charged, the atmosphere was replaced with nitrogen with stirring, and the temperature was raised to 80 ° C. 500 parts of styrene and 50 acrylonitrile from one dropping funnel at the same temperature under a nitrogen stream.
Parts, 150 parts of methyl methacrylate and chain transfer agent A
1.5 parts of the mixture was added dropwise over 5 hours, and simultaneously, a mixture of 6 parts of di-tert-butyl peroxide and 200 parts of xylene was added over 6 hours from the other dropping funnel. After being kept at the same temperature for 3 hours, the solvent and unreacted monomers were distilled off, and styrene-acrylonitrile-methyl methacrylate resin (hereinafter abbreviated as AMS resin-1) 690.
Got a part. The number average molecular weight in this resin is 13,000,
The molecular weight distribution was 1.7.

Comparative Example 2 A styrene-acrylonitrile-methyl methacrylate resin (hereinafter referred to as AMS resin-2) was prepared in the same manner as in Example 1 except that the chain transfer agent A was not used and 10 parts of di-tert-butyl peroxide was used. (Abbreviated as) 690 parts were obtained. The number average molecular weight in this resin was 12,000 and the molecular weight distribution was 3.1.

Test Examples 1-2, Comparative Test Examples 1-2 AS Resin-1, AS Resin-2, AMS Resin-1 and A
MS resin-2 is molded to a thickness of 3 mm, according to JIS
According to the test method of K7105, the light transmittance and haze of the resin were measured using an integrating sphere light transmittance measuring device. Table 1 shows the evaluation results.

[0038]

[Table 1]

[0039]

INDUSTRIAL APPLICABILITY The present invention is a copolymer of styrenes and (meth) acrylonitrile, which has a high light transmittance even though the content of (meth) acrylonitrile is low.
This is to newly provide an acrylic resin. Since the styrene-acrylic resin of the present invention has high light transmittance, it is useful as an optical material such as eyeglass lenses, contact lenses, image reading lenses for copying machines and fax machines, CD-pickup lenses, optical fiber optical disk substrates and the like. is there. The styrene-acrylic resin of the present invention is blended with other transparent resins such as polycarbonate resin, SMA resin and MS resin by changing the (meth) acrylonitrile content without impairing its light transmittance. It is possible to use low birefringence optical materials, etc.
It can also be used as a material for new composite materials.

Front page continuation (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G02B 1/04 G02B 1/04 // G03F 7/033 G03F 7/033 (72) Inventor Yoshimi Kida Higashiyama-ku, Kyoto Sanyo Kasei Kogyo Co., Ltd. 1-11, Hitotsubashi Honcho (72) Nobuo Hisada Inventor No. 1 11-Hitono-cho, Higashiyama-ku, Kyoto Sanyo Kasei Kogyo Co., Ltd.

Claims (7)

[Claims] 1. A radical polymerizable monomer comprising a styrene (A) and a (meth) acrylonitrile (B) and / or a (meth) acrylic acid ester (C), a radical polymerization initiator and the following general compound. A styrene-acrylic resin composition comprising a copolymer (D) obtained by copolymerization in the presence of a chain transfer agent for radical polymerization represented by the formula (1). General formula In the formula, Q is a polyvalent organic group, X ¹ is a carbonyl group or -C
ONH-, A ¹ and A ² are alkylene groups having 1 to 8 carbon atoms, X
² is an oxygen atom, a sulfur atom or an NH group, Z is a chain transfer group, p, q, r and x are 0 or 1 respectively, and m is 1 to 5
An integer of 0 and n are integers of 2 to 100, and may be the same or different in [] and in {} when m is 2 to 50. 2. The resin composition according to claim 1, wherein Z in the general formula (1) is SH. 3. In the general formula (1), p, q, r, x
Are 0 and X ² is an oxygen atom, respectively.
The resin composition as described in the above. 4. The resin composition according to claim 1, wherein styrene is 70% by weight or more as a constitutional unit in the copolymer (D), and light transmittance is 85% or more. . 5. The copolymer (D) has a number average molecular weight of 1,0.
0 to 500,000 and the molecular weight distribution is 1.2 to
It is 3.0, The resin composition in any one of Claims 1-4. 6. The resin composition according to claim 1, wherein the amount of the chain transfer agent is 0.01 to 20% by weight based on the radically polymerizable monomer. 7. The resin composition according to claim 1, which is for an optical material selected from the group consisting of eyeglass lenses, contact lenses, copying machines, fax machines, CD-pickup lenses and optical fiber optical disk substrates.